JPS61210411A - Circuit allowed to select either preset characteristic or user's set characteristic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

FIELD OF THE INVENTION The present invention relates to circuits that enable the implementation of internal preselected characteristics and external user-selectable characteristics in electronic circuits. More specifically, the present invention provides a circuit that allows selection between preset characteristics built into the circuit and user set characteristics that are selectable by the user and communicated with the circuit by means of a display at the input terminal. Regarding.

According to the invention, a circuit having a fixed characteristic of, for example, a DC reference value of +5I, and an output that can be arbitrarily set to any other voltage between the supply voltage values, such as, for example, 1.3I, is provided. Manufacturing becomes possible. Furthermore, the circuit of the present invention has an inherent ability to detect the type of application and can achieve the desired output value by changing the internal circuit configuration and using a single input terminal, thereby performing this function. This eliminates the need to use other input terminals that would normally be required.

BACKGROUND OF THE INVENTION Circuits produced today have either fixed characteristics or user-configurable characteristics. There are also circuits that allow selection of preset characteristics or user set characteristics. However, the same circuit is used when either fixed characteristics or user-configurable characteristics are required, resulting in a versatile circuit.

Electrical circuits operate on electrical quantities, such as voltage, current, frequency, electrical charge, and the like. The magnitude of the electrical quantity is important because it can be used, for example, to form or provide information on the R parameters of a circuit. In digital circuits, high level voltages can be used to represent true logic values, and "false"
A low level voltage can be used to represent the logical value of . Unlike the two levels in the case of binary digital circuits, in the case of analog circuits there are an infinite number of levels between the two limit points in order to proportionally increase and decrease the amount of the characteristic or A parameter. A variable number of voltage levels is available.

There is also a need to provide a circuit that can set a reference level for an electrical quantity. Some of the reference levels have been used so often that they have become standards in the industry. For example, +
DC is a voltage level often used for powering many digital circuits. Similarly, +15 and -1 are the voltage levels when powering analog circuits.
3yN current is often used. Another common group of circuits that create voltage levels are voltage references. Typical voltage reference outputs are +z5, 5 and 10 volts.

However, 1. Unusual voltage levels are also often required, such as in the case of an ayttort, which requires circuitry to operate from a 1.5 volt.

In the past, specialized circuits have been manufactured that have specific characteristics including common (or standard) circuits. In unusual cases, different sets of circuits have been created with non-dedicated, user-selectable characteristics. For example, dedicated +5 or 10
There are voltage standards such as voltage standards or non-power standards that can be set to a particular voltage level, for example by using a simple resistive voltage divider.

Circuits that combine several characteristics are also known. Such circuits typically include inputs for selecting between preset characteristics and user-selectable characteristics to adjust user-selectable amounts. Traditionally, two terminals were required to accomplish this function in a circuit. First, a digital input terminal is required to configure the type of application (i.e.
Second, when using circuits with preset characteristics or user set characteristics, analog input terminals are used as a means for providing user set characteristics.

As circuits and functions become more complex, it is desirable to reduce the number of input and output terminals without incurring any loss of functionality. It is desirable to combine as many functions as possible.

SUMMARY OF THE INVENTION The present invention provides a circuit that allows selection of preset circuit characteristics and user-selectable characteristics, and further allows a user to specify the user-selectable characteristics through a single input terminal. If you offer it, it's seven.

In a preferred embodiment, the characteristic convertible into current, frequency, etc. by known devices is a direct voltage. The DC input voltage at a single input terminal is sensed and compared to the negative supply voltage of the comparator circuit.

If the DC input voltage is equal to the negative DC supply voltage, the switching network transfers the set reference voltage to the voltage follower (voltage follower).
follower) or 'intoxicant follower increase @ vessel carn
rlrf:tr (source followTh) If the DC input voltage exceeds the negative supply voltage, the switching network connects the DC input voltage at the single input terminal to the source follower.

The output of the power supply follower circuit may be made available at the output terminal or may be provided with a circuit parameter other than voltage at the output terminal, such as a voltage-to-DC converter or a voltage-to-frequency converter, etc. It may be connected to other devices.

In a preferred embodiment, the entire circuit can be fabricated on a single semiconductor substrate using OMO8 technology.

OBJECTS AND ADVANTAGES OF THE INVENTION An object of the invention is to provide a circuit that allows selection between user-selectable characteristics and preset characteristics.

It is a further object of the present invention to provide a circuit which allows selection between preset characteristics and user selectable characteristics using a single input terminal.

Another object of the invention is to provide a circuit that is easy to use.

Yet another object of the invention is to provide a circuit that can be relatively easily assembled into larger electronic circuits.

Other features and advantages of the invention will be apparent to those skilled in the art from the following description, having reference to the accompanying drawings and claims.

First, a simplified block diagram of the circuit of the present invention is shown.

The circuit lθ allows selection between user-selectable and preset characteristics via a single input terminal 12. The characteristics shown throughout the following text for illustration purposes only have a constant DC″6
It is L pressure. However, those skilled in the art will readily understand that the present invention encompasses other circuit parameters and characteristics such as current, frequency, etc. This DC voltage is converted into the electronic circuit's current, frequency, and YR Tsukuda's Kuchi's parameter 乃rt.
Those skilled in the art will also know how to do this.

Circuit 1G is capable of selecting between a user-selectable voltage that can be placed at input terminal 12 and an internally set voltage by means of a voltage reference source, such as network 14, consisting of resistor 16 and Zener diode 1B.

The circuit 10 operates by comparing the voltage at the input terminal 12 in a comparator 20 with the negative DC supply voltage (V-) supplied to the circuit. Input terminal 1
If the voltage at 2, ie the input at comparator 20, is equal to the negative supply voltage (indicated by dashed line 21), the output of comparator 20 causes switch 22 to open and switch 24 to close via inverter 26.

When switch 22 is open and switch 24 is closed, internal voltage network 14 connects to the input of voltage tracking amplifier 28.

However, if the voltage at input terminal 12 is greater than the negative supply voltage (indicated by dashed line 29), the output of comparator zO closes switch 22 and switches 24
is opened via the inverter 26. In this case, input terminal 1
The user supply voltage present at 2 is connected to the input of a voltage tracking amplifier 28.

The output of the voltage buffer amplifier 2B is connected to the output terminal 30 as shown in the figure.
or used to operate the circuit, which is commonly used as a voltage-to-frequency or voltage-to-current converter.

In the embodiment of the invention shown in FIG. 1, the voltage applied to the input terminal 12 is a voltage derived from the positive and negative DC supply voltages via a voltage divider 32 comprising, for example, resistors 34 and 36. be.

As will be appreciated by those skilled in the art, some fees may be added to significantly increase accuracy! ! You may also use This embodiment is illustrated in FIG. 2 and described below.

As in the circuit of FIG. 1, the connector 2 of FIG.
0 compares the voltage at input terminal 12 with the negative supply voltage. The outputs of converter 20 and inverter 26 drive switches 22 and 24 to select a preset voltage or a user supplied voltage in the manner described with reference to FIG. However, in the embodiment of FIG. 2, the connections for the two amplifiers 28 are made in the foot knock arrangement.

The output of reference voltage network 14 is provided to a non-inverting input of amplifier 28. Input terminal 12 is connected to the negative supply voltage (dashed line 48
), the output of amplifier 28 is returned to the switching input of amplifier 28 via an internal resistor network consisting of resistors 38 and 40 and switch 24.

As is well known, the gain of amplifier 28 is determined by resistors 38 and 40.
determined by the value of However, the output terminal 30
has resistors 42 and 44 that make it Km (4), and the dashed line 4
When connected to input terminal 12 as shown at 6, amplifier 2B
The output of P is returned to its switching input via a loop consisting of resistors 42 and 44, line 46 and switch 22.

FIG. 3 is a schematic diagram of the embodiment of FIG. 1, with input terminal 100 connected to connector circuit 102. FIG. The controller circuit 102 includes a P-channel device 104, an N
- channel device 106, P-channel circuit 10B and N-channel device 110; N-channel devices 106 and 110 are a matched pair υ, P-channel devices! t104 and 108 are a highly matched pair. P
- Dimensions of channel device 104 are P-channel device 1
The dimensions are slightly larger than 08.

Converter IQ2 is powered by a constant current source 112 consisting of P-channel devices 114 and 116 and N-channel device 118. The amount of current provided by the constant current source 112 allows the reference voltage source 14 of the N-channel device 118 diagram to function satisfactorily for negative DC supply voltages.

Comparator 102 operates as follows. Constant current source 1
12 supplies a constant total current to devices 104 and 06 on one side of comparator 102, and devices 108 and 110 on the other side. P connected to input terminal 100
- If the gate of the channel device 104 is at a negative supply voltage when the device is matched, the currents to both sides are equal. As a result of this imbalance,
The current flowing through devices 104 and 106 is
10.

Hence, the P-channel device! The voltage at the common connection of 10B and N-channel device 110 is the voltage at the common connection of P-channel device 104 and N-channel device 106.
The voltage at part c falls below.

The output at the common connection between the channel device 1110 and the P-channel device 10g is low and the output at the input terminal 12 is low.
Lowers the 0 input and increases the output.

However, the voltage at terminal 100, i.e. P-
If the voltage at the gate of channel d[104 rises above the negative supply voltage, the P-channel device * l 0
4 tends to break. If this happens, the 1 at the common connection gate of N-channel devices 106 and 110
The voltage moves towards the negative DC supply voltage and turns off the device. The voltage at the output of the comparator therefore rises, presenting a high level at the input of inverter 120, thereby causing its output to be low.

Inverter 12 connected to the output of comparator 102
0 consists of an N-channel device 122 and a P-channel device @124 connected in series with their gates interconnected. When the input voltage to the gate is low, the N-channel device 12 at or near the negative supply voltage
2 is off and the P-channel device 124 is on. Thus, the output of the innovator 120, the common source/F line connection of devices 122 and 124, will be high. When the input is high, the N-channel device 122 is on and the P-channel device 124 is off, thus causing the output to be low.

Switches 126 and 128 are connected to N-channel device 13.
0, a P-channel device 132, an N-channel device 134, and a KP-channel device 136, respectively. P-channel equipment 132 and N-channel equipment! The gate of JjIt 134 is connected to the output of inverter 120. The gates of N-channel device 11 30 and P-channel device 136 are connected to a common connection between the output of converter 102 and the input of inverter 120.

In the first case with a negative supply voltage at the terminal ZOO (selecting the preset characteristic) and thus with a low input and high output of the inverter 120, the N connected to the input of the inverter 120 is
- a P-channel device connected to the channel device 130 and the output of the inverter [132 is turned on, an N-channel device 134 connected to the output of the inverter and a P-channel device connected to the input of the inverter ff1ta;
6 tends to be off. switch 126 is closed;
Switch 128 is open.

For similar reasons, when the input to input 120 is high and its output is low, switch 128 closes and switch 1
26 opens.

Depending on which switch 126 or 128 closes, either the reference voltage (Vref) or the user supplied voltage at input terminal 100 is connected to the source
amplifier 138 configured as
supplied to Standard voltage of amplifier 138 (Vrsf)
or the user supplied voltage at input terminal 100.

As will now be apparent to those skilled in the art from FIG. 4, the embodiment shown here is similar in most respects to that of FIG. The connections between the switches 126 and 128 and the buffer amplifier and output terminals reflect the use of different switch and foot contacts.

In the embodiment of FIG. 4, a feedback main section is used to stabilize the accuracy of the output section and make it easier to control. In this embodiment, an internal feed barrier cruise consisting of resistors 6140 and 142 and resistors 144 and 146
Users can choose between a variety of available external feeds and cruises.

In the fourth embodiment, the non-inverting input of amplifier 5138 is provided by, for example, the Zener diode resistor network 14 of FIGS. Their common connection is switch 12
Connect 81C. The external feedthrough consists of resistors 144 and 146 whose common connection connects to switch 126 via input terminal 100.

In the embodiment of FIG. 4, the input terminal 100 is connected to the dashed line 148
When connected to a negative DC supply voltage as shown at , switch 128 is closed and switch 126 is open. Therefore,
If an internal feed barrier circuit is possible that connects the amplifier 13g, the voltage that appears at the output terminal 139 can be controlled by the resistor 140.
and 142 and the reference voltage (Vref).

However, if input terminal 100 is connected to the junction of resistors 144 and 146 as shown by dashed line 150, then
Switch 126 is closed and switch 128 is opened, creating an external foot loop through amplifier 138t. Therefore, the voltage at output terminal 139 is across resistor 144
and 146, and the value of the reference voltage (Vref).

As will be understood by those skilled in the art, 0M using N-channel and P-channel enhancement devices
Although a preferred embodiment of O8 has been described, devices such as depletion devices and O9 polar function transistors may also be used. Additionally, although not shown in FIGS. 3 and 4, it will be apparent to those skilled in the art that the substrates of all N-channel devices are connected to the negative DC supply voltage, and the substrates of P-channel devices are connected to the positive DC supply voltage. Connect to DC supply voltage.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a preferred embodiment of the present invention;
FIG. 2 is a block diagram illustrating another preferred embodiment of the invention that uses feedback to improve accuracy and stability;
3 is a schematic diagram of the embodiment of FIG. 1, and FIG. 4 is a schematic diagram of the embodiment of FIG. 2. 10...Circuit, 12,100...Input terminal, 14...Circuit network, 16,34.3g, 4
0,42゜44.140,142,144,146...
...Resistor, 18...Zener diode, 20,102...Connogrator, 22.2
41126,128...Switch, 26,12
0...Inverter, 28...Amplifier,
30.139...Output terminal, 32...
Voltage divider, 104.108.114.116°124.1
32,136...P-channel device, 106
．． 110.118.122, 130, 134° N-channel device, 112... constant current source. +X, - person 11 Kawaguchi Yoshi Yutoki Kari'''' Mi1

Claims (1)

[Claims] A single input terminal, a first voltage supplied by a user to the single input terminal and a second voltage inside the circuit, wherein the first voltage is 2
a comparator device having an output section that takes a first state when the first voltage is equal to or less than the second voltage; and a comparator device that takes the second state when the first voltage exceeds the second voltage; a first control element connected between and responsive to the output of the comparator to open when the output is in the first state and close when the output is in the second state; a switch connected between an internal voltage source and the output terminal, the output of the comparator being closed when the output is in the first state and open when the output is in the second state; an integratable circuit for selecting internal preset parameters and user selectable externally supplied parameters, the circuit comprising: a second switch having a control element connected thereto and responsive thereto;