KR101096102B1 - Delay time counting circuit and touch sensor with the same - Google Patents

Abstract

The present invention relates to a delay time measuring circuit and a touch sensor having the same. In the present invention, an oscillation frequency is changed according to an impedance value applied from the outside, and a gate delay is generated regardless of a clock according to the changed oscillation frequency. A delay oscillation pulse generator for oscillating a predetermined number of times and outputting a pulse signal having a pulse width that varies according to the oscillation period, and a pulse width counter unit for counting the pulse width of the pulse signal output from the delay oscillation pulse generator; A delay time measuring circuit and a touch sensor having the same are presented.

Touch sensor; Capacitive touch sensor; Touch circuit

Description

Delay time measuring circuit and touch sensor having same {DELAY TIME COUNTING CIRCUIT AND TOUCH SENSOR WITH THE SAME}

The present invention relates to a delay time measuring circuit and a touch sensor having the same. More specifically, the present invention relates to a delay that can accurately determine a pressed position of a capacitive touch panel and further determine a state in which the touch panel is not in direct contact with the touch panel. It relates to a time measuring circuit and a touch sensor having the same.

Touch panel devices are widely used as one of input means of display devices. The touch panel device includes a touch panel in which a touch pad is patterned and directly touched by a user's finger, and a touch sensor that determines which pad is touched by analyzing an electrical signal input from the touch panel.

The method of improving the touch sensitivity in the touch panel device requires a high-sensitivity touch sensor capable of finely forming a pattern of the touch panel and accurately determining whether each of the patterned touch pads is pressed or not pressed.

The delay time measuring circuit measures a time from a reference time at which measurement starts until a signal to be measured is applied, and outputs a value corresponding to the measured time. Also called digital conversion circuit. A delay time measuring circuit that can output time-domain values as digital data is applied to various electronic devices. Generally, a reference signal for specifying a measurement start time and a measurement signal to be measured are applied to a reference signal. Measure the delay time of the measured signal. Here, the delay time measuring circuit can measure the delay time in various ways, and a representative method is a method of measuring the delay time with a delay chain.

1 is a diagram illustrating a delay time measuring circuit measuring delay time by using a delay chain as an example of a conventional delay time measuring circuit. 1 is a diagram shown in Patent Application No. 2005-117183 (hereinafter referred to as Cited Invention), which is a sensor or an analog-to-digital converter for measuring a delay time difference by converting a change in impedance or voltage into a delay time difference. In FIG. 1, the delay time measuring circuit 1 includes a read signal generator 10, a reset signal generator 20, a delay chain 30, a thermometer code generator 40, and a binary code decoder 50. .

The read signal generation unit 10 includes an inverter I1 for inverting and delaying the reference signal ref, inverters I2 and I3 for delaying the measurement signal sen, and delayed measurement with the inverted and delayed reference signal ref. AND gate AND1 for generating a read signal clocked in synchronization with the rising edge of the inverted and delayed reference signal ref by multiplying the signal sen, and the reset signal generator 20 measures Inverters I4 and I5 that delay the signal sen, and exclusively OR the delayed measurement signal sen and the non-delayed measurement signal sen to clock in synchronization with the rising and falling edges of the measurement signal sen. Generates a reset signal that is clocked in synchronization with the falling edge of the delayed measurement signal sen by multiplying the output signal of the XOR gate XOR and the output signal of the XOR gate XOR and the delayed measurement signal sen that generate the signal And AND gate AND2.

In this case, the read signal read is generated through the even-numbered inverters I2 and I3 and the AND gate AND1, while the reset signal is the even-numbered inverters I4 and I5 and the XOR gate XOR. And a read signal read is clocked before the reset signal reset because it is generated through the AND gate AND2. That is, since the reset signal reset is generated through one logic gate XOR more than the read signal read, the read signal read is clocked before the reset signal reset.

The delay chain 30 is composed of a plurality of delay elements D1 to D7 connected in series to delay the reference signal ref to generate a plurality of delay signals delay1 to delay7. The thermometer code generator 40 ) Latches the measurement signal sen in response to the delay signals delay1 to delay7 to generate a plurality of output signals Q1 to Q7 and are reset by the reset signal reset. A plurality of NAND gates that generate a thermometer code by performing negative AND on the output signals Q1 to Q7 and the read signals read of the FF1 to D-FF7 and the plurality of D flip-flops D-FF1 to D-FF7 (NAND1 to NAND7), the binary code decoder 50 is implemented as a binary code decoder for converting the thermometer code into a binary code (b_code).

The operation of the delay time measuring circuit 1 of FIG. 1 will be described with reference to FIG. 2. First, when the delay time measuring circuit 1 receives the reference signal ref and the measurement signal sen having the same delay time, the following operation is performed.

The delay chain 30 delays the reference signal ref through the plurality of delay elements D1 to D7 to generate a plurality of delay signals delay1 to delay7 having different delay times, and all D flip-flops. (D-FF1 to D-FF7) latch the measurement signal (sen) having a high level in synchronization with the rising edge of each of the delay signals (delay1 to delay7) to receive the high level output signals (Q1 to Q7). Occurs.

After a predetermined time elapses, when the read signal read is clocked, the plurality of NAND gates NAND1 to NAND7 negatively multiply the read signal read and the plurality of output signals Q1 to Q7 to zero. Branch generates a thermometer code (0000000).

The binary code decoder 50 receives a thermometer code (0000000) having a value of 0, converts the received thermometer code (0000000) into a binary code (b_code), and outputs it.

However, when the reference signal ref having the delay time difference tdiff and the measurement signal sen are applied to the delay time measurement circuit 1, the predetermined D flip-flops D-FF1 delay the measurement signal sen. Receive delay signals delay1 having a delay time smaller than the time, and the remaining D flip-flops D-FF2 to D-FF7 receive delay signals having a delay time larger than the delay time of the measurement signal sen. delay2 ~ delay7) will be received.

The predetermined D flip-flops D-FF1 latch the low-level measurement signal sen to generate low-level signals Q1, and the remaining D-flop flops D-FF2 to D-FF7. In the same manner as before, the latches the high level measurement signal sen to generate the high level signals Q2 to Q7.

When a predetermined time elapses and the read signal is clocked, the plurality of NAND gates NAND1 to NAND7 may output the output signals Q1 to Q7 of the plurality of D flip-flops D-FF1 to D-FF7. To generate a thermometer code (1000000). That is, a thermometer code 1000000 having a value corresponding to the delay time difference between the reference signal ref and the measurement signal sen is generated.

The binary code decoder 50 receives a thermometer code 1000000 having a value corresponding to the delay time difference, converts it into a binary code b_code, and outputs the converted code.

As described above, in the delay time measuring circuit 1, the plurality of D flip-flops D-FF1 to D-FF7 have different levels according to the delay time difference tdiff of the reference signal ref and the measurement signal sen. The output signals Q1 to Q7 are output so that the delay time difference tdiff between the reference signal ref and the measurement signal sen can be calculated.

The delay time measuring circuit 1 shown in FIG. 1 has a problem in that the delay times of the plurality of delay elements D1 to D7 constituting the delay chain 30 must be exactly coincident in order to increase the accuracy. In addition, when some noise is included in the measurement time (sen), there was a problem in that the accurate delay time of the measurement time could not be measured, and when the delay time to be measured was short, accurate measurement was difficult.

The present invention is to solve the problems as described above, even when the delay time to be measured is accurate, the delay time measuring circuit does not need to add a separate circuit even if you want to measure high accuracy and this It is an object to provide a touch sensor provided.

An object of the present invention is to provide a delay time measuring circuit that can determine whether the correct touch according to changes in ambient temperature, humidity and voltage, and a touch sensor having the same.

The object of the present invention is that the oscillation frequency is changed according to the impedance value applied from the outside, the oscillation frequency is oscillated a predetermined number of times using a gate delay generated irrespective of the clock in accordance with the changed oscillation frequency, and the pulse width changed according to the oscillation period A delay time measurement circuit can be achieved by including a delay oscillation pulse generation unit for outputting a pulse signal having a pulse width counter unit for counting the pulse width of the pulse signal output from the delay oscillation pulse generation unit.

Still another object of the present invention is to provide a touch sensor for measuring impedance that changes according to whether or not a touch is provided. An oscillation frequency is changed according to an impedance value applied from the outside, and a gate delay generated regardless of a clock according to the changed oscillation frequency is determined. A delayed oscillation pulse generator for oscillating a predetermined number of times and outputting a pulse signal having a pulse width that varies according to the oscillation period, and a pulse width counter unit for counting the pulse width of the pulse signal output from the delayed oscillation pulse generator; And a reference value storage unit for storing a reference value which is an output value of the pulse width counter when the impedance is not touched, and an operation control unit for comparing the output value of the pulse width counter unit with the reference value stored in the reference value storage unit to determine whether the touch is performed. It can be achieved by the touch sensor.

The delay time measuring circuit of the present invention repeats a predetermined number of oscillation waveforms having a frequency that changes according to an externally applied impedance, and adds them analogically, so that the delay time is more precisely compared with the conventional delay time measuring circuit. It became measurable. Therefore, it is possible to increase the number of oscillations of the oscillation circuit even when the delay time to be measured is short, so that accurate measurement is possible, and there is no need to add a separate circuit to measure the accuracy with high accuracy.

In addition, in the present invention, the pulse width counter to be used is implemented so that the clock resolution can be changed, so that the touch can be more accurately determined when the impedance applied from the outside is changed according to the user's touch. Furthermore, when the impedance applied from the outside is the capacitive impedance, it is possible to detect a minute change in capacitance generated just before the user's body touches the touchpad. Therefore, it is possible to present a function of detecting a minute change to partially enlarge a part of the screen that the user wants to touch.

In addition, the touch sensor of the present invention can easily change the reference value of the impedance to determine whether the touch if the reference value of the impedance is finely changed for more than a certain period in accordance with the change of the ambient temperature, humidity and voltage to determine whether more accurate touch This made it possible.

Hereinafter, the advantages, features and preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a delay time measuring circuit according to an embodiment of the present invention. As shown in FIG. 3, the delay time measuring circuit according to the present invention includes a delay oscillation pulse generator, a pulse width counter, and an operation controller. The delayed oscillation pulse generator changes the oscillation frequency according to the externally applied impedance value Zsen and oscillates a predetermined number of times using a gate delay without using an internal clock according to the changed oscillation frequency, and changes according to the oscillation period. A pulse signal having a width is output. The pulse width counter unit counts the pulse width of the pulse signal output from the delayed oscillation pulse generator and outputs it. The operation control unit applies a start signal to the delayed oscillation pulse generator and controls the delayed oscillation pulse generator and the pulse width counter to terminate the start signal by receiving an end signal generated by an external clock asynchronously. Function

4 is a block diagram illustrating an input signal and an output signal of a delayed oscillation pulse generator, and a timing diagram of an input signal and an output signal. As shown in FIG. 4A, the delayed oscillation pulse generator outputs a pulse signal and a finish signal after receiving the oscillation repetition number repeat [] and the start signal strat. The delayed oscillation pulse generator may be configured as a relaxation oscillator or a ring oscillator.

An operation of the delayed oscillation pulse generator according to the present invention will be described with reference to FIG. 4 (b). When the start signal (start) is input after the oscillation repetition number '3' is input from the operation control unit, the delayed oscillator or the ring oscillator oscillates the wave shown in the waveform by the oscillation repetition number '3'. The end signal (finish) is activated at the end of three oscillations, and the pulse signal (pulse) is a pulse signal having a pulse width from the moment the start signal (start) is activated until the end signal (finish) is activated Output After that, the finish signal (finish) is input to the operation control unit, the operation control unit recognizes that the oscillation is finished in accordance with the input end signal (finish) and generates a clock tick to initialize the delayed oscillation pulse generator. Clock tick indicates the system clock used by the latency measurement circuit.

As shown in FIG. 4C, the oscillation waveform oscillates by the number of oscillations (three times in FIG. 4) according to the oscillation frequency after passing the oscillation start delay time Td after the start signal is applied. Proceed). The oscillation start delay time Td and oscillation frequency To change according to an impedance value applied from the outside. Therefore, when the number of oscillations inputted to the delay oscillation pulse generator is increased, the delay time generated by the external impedance value can be added analogously, so that accurate measurement can be performed even with a small delay time. That is, by adjusting the number of oscillations, the resolution of the delay time due to the external impedance to be measured can be adjusted.

5 illustrates waveforms generated when the delayed oscillation pulse generator according to the present invention comprises a delayed oscillator and a ring oscillator. When the delayed oscillation pulse generating unit is implemented with a delayed oscillator having a pull-up resistor (R) and an open-drain structure (FIG. 5 (a)), the power source is applied from the pull-up resistor (R) when the waveform is rising and the driving stage is lowered when the waveform is rising. The oscillation signal of the form as shown in FIG. 5 (b) is output using the output. When the delayed oscillation pulse generating unit is implemented by a ring oscillator having an odd number of inverters (Fig. 5 (c)), the rising frequency and the falling waveform have an output waveform (Fig. 5 (d)) in which the output of the driving stage is made high frequency. You can generate

6 is a circuit diagram of a specific gate level in which a delay oscillation pulse generator is implemented as a ring oscillator according to the present invention. The delayed oscillation pulse generator of FIG. 6 is operated according to the timing diagram shown in FIG. The delayed oscillation pulse generator according to the present invention includes first latches L2 and L3 for countering the number of oscillations, a gate g4 for receiving a start signal, and gates g1 and g2 for implementing an oscillation waveform including an odd number of inverters. , g3) and an end signal indicating that the oscillation is completed by the number of oscillations using the match signal input from the comparator and the comparator which generate a coincidence signal when the oscillation number inputted from the operation control unit and the output value of the first latch are matched. It includes a second latch (L1) for outputting.
The repetition number repeat [] is predetermined from the operation control unit. Next, when the start signal start is applied, the gate g4 is activated and the pulse signal pulse is activated. The NAND gate g3 then sets the input terminal from the AND gate g4 to " 1 " and outputs a value inverted from that of the other input terminal of the NAND gate g3. Therefore, an oscillation signal having an oscillation frequency changed according to external impedance is generated through a ring oscillator using a gate composed of two buffers g1 and g2 and a NAND gate g3. The delayed oscillation pulse generator according to the present invention generates an oscillation using only a gate delay configured without a separate clock applied externally or internally according to a given start signal. This feature has the advantage that it is possible to accurately measure the delay time by analogizing the delay signal generated by the applied external impedance. The number of oscillations of the ring oscillator is stored in the first latches L2 and L3 constituted by the ripple counter, and the comparator is assigned to the second latch L1 if it is equal to the number of repeats [repeat [] applied from the operation control unit through the comparator. Inform that the number of times is reached. The output signal of the second latch L1 generates a finish signal, also deactivates the gate g4, and subsequently deactivates the pulse signal pulse. As the output signal of the gate g4 is inactivated, the NAND gate g3 is inactivated, and the oscillation circuit ends oscillation. The finish signal (finish) is input to the operation control unit to inform that the oscillation is completed by the specified number of oscillations.

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7 illustrates input and output signal waveforms of a delayed oscillation pulse generator according to the present invention generated according to an applied external impedance value. FIG. 7A illustrates a case where the external impedance value is small, and FIG. 7B illustrates a case where the external impedance value is large. It can be seen that the oscillation frequency is smaller and the pulse width of the output pulse signal pulse is smaller than the case where the external impedance value is small.

8 is a circuit diagram of a pulse width counter of one embodiment according to the present invention. As shown in FIG. 8 (a), the pulse width counter receives a pulse signal input from a delay oscillation pulse generator and a resolution and initialization signal set from an operation control unit. The value is output as a data signal data []. 8B illustrates an example in which the pulse width counter is implemented as a clock generator and a pulse counter. The clock generator generates and outputs a clock signal according to a period determined by the resolution while the pulse width of the input pulse signal is activated, and the pulse counter counts the input clock signal and counts The value is output as a data signal data [].

9 is a block diagram of a clock generator circuit in one embodiment according to the present invention. As illustrated in FIG. 9A, a clock corresponding to the pulse width of the pulse signal is generated using a plurality of muxes MUX having a resolution []. FIG. 9B shows the pulse signal inputted to FIG. 9A and the clock signal outputted.

10 illustrates an example of implementing a pulse counter of one embodiment according to the present invention. As shown in FIG. 10, the pulse counter is an example of forming a plurality of latches as a ripple counter. In FIG. 10, a clock signal is a signal output from a clock generator, and an initialization signal set is input from an operation control unit and used to initialize a latch.

11 is a configuration example of a touch panel device to which a touch sensor according to an embodiment of the present invention is applied. As illustrated in FIG. 11, the touch panel apparatus may be configured to determine which touch pad is touched by analyzing a touch panel 200 having a touch pad patterned thereon and directly contacting a user's finger with an electrical signal input from the touch panel. It consists of a touch sensor 100. In FIG. 11, the capacitive touch panel device is illustrated, and the touch panel 200 has N touch pads in a pattern, which is briefly represented as N capacitive impedances (1st Csen, 2nd Csen, and Nth Csen).

The touch sensor according to the present invention includes a delay oscillation pulse generator and a pulse width counter connected to the capacitive impedance, an operation controller and a reference value storage. In FIG. 11, the delay time measuring circuit 52 is composed of only a delay oscillation pulse generator and a pulse width counter, which indicates that the operation controller used for the touch sensor is more complicated than the operation controller used for the delay time measurement circuit. Since it is in charge of control, it is omitted. Therefore, some functions of the calculation control unit should also be interpreted as being included in the delay time measuring circuit 52. Since the delayed oscillation pulse generator and the pulse width counter have the same configuration as the description of the delay time measurement circuit described above, description thereof will be omitted. The operation control unit repeats the delayed oscillation pulse generator Specify the number of times (repeat []), apply a start signal (start), and receives the end signal (finish) generated from the delayed oscillation pulse generator to control the system clock, and also the pulse width counter It receives a count (data []) output from the input, and compares it with the value stored in the reference value storage to determine whether the touch pad touches and changes the reference value. The reference value storage unit may store a reference value, a threshold value, and a noise value of each touch pad. The reference value storage unit may use a memory included in the operation control unit, or may use a memory separate from the operation control unit.

12 is a timing diagram illustrating an oscillator operation sequence of a delayed oscillation pulse generator according to an embodiment of the present invention. In the drawings, the numerals indicated inside the rectangles show a delayed oscillation pulse generating unit and a pulse width counter unit constituting a touch sensor connected to the touch pad. For example, a rectangle having '1' therein shows a timing at which the delayed oscillation pulse generator and the pulse width counter are connected to the first capacitive impedance. FIG. 12 (a) shows how circuits connected with each capacitive impedance are operated sequentially, and FIG. 12 (b) shows how circuits connected with each capacitive impedance are operated simultaneously. The touch sensor according to the present invention may be operated in any of the two methods shown in FIG. 12, and although not shown in the drawing, the touch sensor may be operated in a group.

FIG. 13 illustrates a state diagram for determining a state of a touch pad using a counter value data [] output from a pulse width counter of a touch sensor according to the present invention, and FIG. 14 illustrates a touch sensor according to the present invention. In the control calculator, a touch pad detects a state. An operation of determining whether a touch is made using the touch sensor according to the present invention will be described with reference to FIGS. 13 and 14.

In FIG. 13, the number indicated on the left side of the graph indicates a count value data [] output from the current pulse width count, and the underlined number indicates a coded value. Reference values, noise values, and threshold values of each capacitive impedance are stored in the reference value storage. The reference value is a count value output to the pulse width count assuming that each capacitive impedance is not charged, and the noise value represents an allowable error range of the count value output from the pulse width count. The value is a threshold for determining that each capacitive impedance has been touched.

The coded value is a value obtained by comparing a previously stored reference value with a currently read counter value. The code '0' indicates that the currently read counter value is smaller than the previously stored reference value, and the code '1' previously The currently read counter value is larger than the stored reference value within the noise value range, and the code '2' is larger than the previously stored reference value and the counter value currently read exceeds the noise value range and is larger than the threshold value. The code '3' indicates that the currently read counter value is larger than the previously stored reference value while exceeding the threshold range. When the comparison code is '3', it is recognized that a touch has occurred in the corresponding capacitive impedance, and when the comparison code is not '3', it is determined that the capacitive impedance is not touched.

Hereinafter, reference values and various code values will be described using specific numerical values shown in FIG. 13. 13 assumes that the counter value data [] of the previously stored capacitive impedance is the reference value '2', the noise value is '2', and the threshold value is '6'. The comparison code is determined using the limit value after the capacitive impedance previously stored in the pulse width counter data [] of the currently read capacitive impedance limits the pulse width counter value data [].

For example, if the current read counter value data [] of the capacitive impedance is '3', the comparison code is stored as '1'. This is because the pulse width counter (data [] = 3) of the capacitive impedance currently read out is limited to the pulse width counter value (data [] = 2) of the previously stored capacitive impedance, and the limit value (1) is larger than the reference value. Since it is in the range of the value (2), it is determined by the comparison code '0'. In the same way, if the currently read pulse width counter value data [] of capacitive impedance is '1', the comparison code is stored as '0', and the currently read pulse width counter value data [] of capacitive impedance is stored. ) Is '5', the comparison code is stored as '2', and finally, if the capacitive impedance currently read capacitive pulse width counter value (data []) is '9', the comparison code is stored as '3'.

The touch sensor according to the present invention can change the reference value according to the ambient temperature, humidity, voltage, so that it is possible to determine whether the correct touch. The operation of the touch sensor will be described using the flowchart of FIG. 14.

When the touch sensor is driven, the comparison counter and the storage code value of the operation control unit are initialized to '0', and the touch sensor is operated once to set the output value of the pulse width counter as a reference value (S1). After that, the touch sensor is operated again to read the output value of the pulse width counter (S3). A comparison code is generated by comparing the output value of the newly read pulse width counter with a reference value (S4). The storage code and the comparison code are compared to determine whether they are the same value (S5). If the value is the same, the comparison counter is increased to '1' (S6). Then, it is determined whether the comparison code is '1' and an overflow occurs in the comparison counter (S7). If the determination result is true, the reference value is changed to the output value of the pulse width counter currently read, that is, the reference value is increased (S8). In operation S3, the touch circuit receives a new value. It is determined whether step S7 is not satisfied and the comparison code is '0' and an overflow occurs in the comparison counter (S9). If the determination result is true, the reference value is changed to the output value of the currently read pulse width counter, that is, the reference value is decreased. In operation S8, the touch circuit is operated again to receive a new value (S3). When the determination result of step S5 is not satisfied, the comparison counter is initialized (S11), the comparison code value is stored (S12), and the touch circuit is operated again to receive a new value (S3).

As described with reference to the flowchart of FIG. 4, the touch circuit according to the present invention can update the reference value by itself. For example, if the capacity of an externally applied capacitive capacitor decreases in response to external temperature or humidity, the pulse width counter value will be decreased, and the comparison code generated in step S4 is generated as '0'. When the condition that the comparison counter overflows is satisfied, the reference value is changed to a value lower than the currently set reference value. Similarly, if the capacity of the externally applied capacitive capacitor continues to increase in response to external temperature or humidity, the pulse width counter value will decrease, and the comparison code generated in step S4 is generated as '1'. If the condition that the comparison counter overflows is satisfied, the reference value is changed to a value higher than the currently set reference value. By using the principle of changing the reference value, the touch sensor according to the present invention is able to determine whether the correct touch, even if the ambient temperature, humidity and voltage changes.

Although specific embodiments of the present invention have been described and illustrated above, it will be apparent that various modifications may be made by those skilled in the art without departing from the technical spirit of the present invention. Such modified embodiments should not be understood individually from the spirit and scope of the present invention, but should fall within the claims appended to the present invention.

1 is a diagram illustrating a delay time measuring circuit for measuring a delay time using a delay chain as an example of a conventional delay time measuring circuit.

2 illustrates the operation of the delay time measuring circuit 1 of FIG. 1 with reference to FIG.

3 is a block diagram of a delay time measuring circuit of one embodiment according to the present invention;

4 is a block diagram illustrating an input signal and an output signal of a delayed oscillation pulse generator, and a timing diagram of an input signal and an output signal.

5 is a waveform diagram generated when the delayed oscillation pulse generator according to the present invention comprises a delayed oscillator and a ring oscillator.

6 is a circuit diagram of a specific gate level in which a delay oscillation pulse generator is implemented as a ring oscillator according to the present invention.

7 is an input and output signal waveform diagram of a delayed oscillation pulse generator according to the present invention generated according to an applied external impedance value.

8 is a circuit diagram of a pulse width counter of one embodiment according to the present invention.

9 is a block diagram of a clock generator circuit in one embodiment according to the present invention.

10 is an example of implementing a pulse counter of one embodiment according to the present invention.

11 is a configuration example of a touch panel device to which a touch sensor according to an embodiment of the present invention is applied.

12 is a timing diagram illustrating an oscillator operation sequence of a delayed oscillation pulse generator according to an embodiment of the present invention.

13 is a state diagram for determining a state of a touch pad using a counter value data [] output from a pulse width counter of a touch sensor according to the present invention.

14 is a flow chart to determine the state of the touch pad in the control calculation unit of the touch sensor according to the present invention.

***** Brief description of the main parts of the drawing ******

52: delay time measuring circuit 100: touch sensor

200: touch panel

Claims (16)

delete delete delete The oscillation frequency is changed according to the impedance value applied from the outside, the oscillation frequency is oscillated a predetermined number of times using a gate delay generated irrespective of the clock according to the changed oscillation frequency, and a pulse signal having a pulse width changed according to the oscillation period is output. A delayed oscillation pulse generator, A pulse width counter unit for counting a pulse width of a pulse signal output from the delayed oscillation pulse generator; An operation control unit for applying a start signal and the number of oscillations; The delayed oscillation pulse generator A first latch for countering the number of oscillations; A gate receiving the start signal and A gate for implementing an oscillation waveform having an odd number of inverters, A comparator configured to compare the number of oscillations inputted from the operation control unit with an output value of the first latch and to generate a coincidence signal when they match; And a second latch outputting an end signal indicating that the oscillation is completed by the number of oscillations by using the coincidence signal input from the comparator. The method of claim 4, wherein The pulse width counter may include a clock generator configured to output a plurality of clock signals corresponding to the pulse width of the pulse signal after receiving a pulse signal output from the delayed oscillation pulse generator; And And a pulse counter for counting the generated clock signal. The method of claim 5, The clock generator is a delay time measurement circuit, characterized in that the resolution can be adjusted to change the generated clock cycle to interpret the pulse signal. delete delete delete delete In the touch sensor for measuring the impedance that changes depending on whether the touch, The oscillation frequency is changed according to the impedance value applied from the outside, the oscillation frequency is oscillated a predetermined number of times using a gate delay generated irrespective of the clock according to the changed oscillation frequency, and a pulse signal having a pulse width changed according to the oscillation period is output. A delayed oscillation pulse generator, A pulse width counter unit for counting a pulse width of a pulse signal output from the delayed oscillation pulse generator; A reference value storage unit for storing a reference value which is an output value of a pulse width counter when the impedance is not touched; Comprising an operation control unit for comparing the output value of the pulse width counter unit and the reference value stored in the reference value storage unit to determine whether the touch, and applying the start signal and the number of oscillation to the delay oscillation pulse generation unit, The delayed oscillation pulse generator A first latch for countering the number of oscillations; A gate receiving the start signal; A gate for implementing an oscillation waveform having an odd number of inverters, A comparator configured to compare the number of oscillations inputted from the operation control unit with an output value of the first latch and to generate a match signal when they match with each other; And a second latch for outputting an end signal indicating that the oscillation is completed by the number of oscillations by using the coincidence signal input from the comparator. The method of claim 11, The pulse width counter may include a clock generator configured to output a plurality of clock signals corresponding to the pulse width of the pulse signal after receiving a pulse signal output from the delayed oscillation pulse generator; And And a pulse counter for counting the generated clock signal. The method of claim 11, The clock generator is a touch sensor, characterized in that for changing the clock cycle is generated to adjust the resolution to interpret the pulse signal. The method of claim 11, The reference value storage unit further includes a noise value indicating a permissible error range of the count value output from the pulse width count and a threshold value which is a threshold value for determining that each capacitive impedance is touched. The method of claim 11, And the calculation controller increases the reference value when the output value of the newly recognized pulse width counter is larger than the reference value stored in the reference value storage unit. The method of claim 11, And the calculation control unit decreases the reference value when the output value of the newly recognized pulse width counter is smaller than the reference value stored in the reference value storage unit.

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