TWI312869B - Power level detector - Google Patents

Description

1312869 IX. Description of the invention: [Technical field to which the invention pertains] This case relates to a voltage source level detector. [Previous Technique #Ϊ] Figure 1 is a conventional voltage source level detecting device for detecting the level of the voltage source VDD used by a chip, including a bandgap reference voltage generator ( A Bandgap Voltage Generator 102, a debt measurement voltage generating circuit 104, and a comparator CMP. The bandgap reference voltage generator 102 is commonly found in general integrated circuit chips and is used to generate a bandgap reference dust VBG for wafer reference. The bandgap reference voltage vBG is a fixed value (typically 1.25 volts) that is unaffected by temperature and does not drift with the voltage source vDD. The town voltage measuring circuit 1〇4 includes three transistors (M1, M2, and M3) and two resistors (the core is used to divide the voltage source after the bandgap reference voltage is generated). VDD, a detection voltage Vdet is generated. As shown in Fig. 1, after the bandgap reference voltage VBG is generated, the transistor Mi is turned on, the cell is turned on, the cell is operated in the saturation region (saturati〇11 region), and the transistor is导? is turned on and generates a current flowing through the resistor core and r2. Since the area of the transistor Mg is much larger than the transistor m2, the transistor m3 operates in a linear region and operates in a resistive mode, and the resistance value thereof is The resistors Ron, R1, and R2 divide the voltage source VDD and output the detection voltage Vdet. The comparator CMP compares the detection voltage Vdet with the bandgap reference voltage VBG and then 'rounds a flag Flag to compare Result, for judgment

Client’s Docket No.: VTT〇6-〇147 TT's Docket No:0608-A41〇〇5.TW/Final /Glorious_Tien £1312869 Voltage source vDD current level. However, when the voltage source VDD is reset, the conventional voltage source level detecting device 100 often causes an error. Because the bandgap reference voltage generator 102 does not immediately generate the bandgap reference voltage VBG after the voltage source VDD is reset; the bandgap reference voltage must be generated after the voltage source VDD returns to a level. VBG. For example, assuming that VDD is 5V, after the voltage source VDD is reset, the bandgap reference voltage generator 102 does not initially output the bandgap reference voltage VBG, and must wait until the voltage source VDD rises to a level. The bandgap reference cell VBG is generated after the bit (for example, 2.5V). As a result, after the voltage source VDD is reset and has not recovered to the level, the two input signals of the comparator CMP (the gap reference voltage VBG and the detection voltage Vdet) are not yet prepared. Ok, so the operation of the comparator CMP will be wrong. SUMMARY OF THE INVENTION The present invention provides a novel voltage source level detecting device that avoids the problems that occur when the conventional voltage source level detecting device 100 is reset at a voltage source. The voltage source level detecting device proposed by the present invention comprises a voltage source voltage divider, a bandgap reference voltage generator, a comparison circuit, a control circuit, and a forcing circuit. The voltage source voltage divider is used to divide a voltage source to generate a detection voltage. After resetting the voltage source, the bandgap reference voltage generator generates a bandgap reference voltage after the voltage source returns to a level. The comparison circuit is configured to compare the detection voltage and the gap reference voltage to determine the level of the voltage source. The energy gap reference voltage is still

Client's Docket No.:VIT06-0147 TT's Docket No:0608-A41005-TW/Final /Glorious Tien ( 1312869 When not generated 'The control circuit will disable the gap reference voltage generated, the control circuit is gone The comparison circuit can enable the comparison circuit to be controlled by the comparison circuit control circuit, wherein the comparison circuit is in a de-energized state, and the second forcing circuit forces the voltage of the output terminal of the comparison circuit to be constant. The value is to prevent the comparison circuit from rotating the error message. The present invention and the other objects, features, and advantages will be more apparent, and the members will be more important, and the preferred embodiment will be described below. 2 is a schematic diagram of a voltage source level detection skirt of the present invention, wherein the '-voltage source level detecting device 2 〇〇 includes a voltage source voltage divider The gap reference voltage generator 204, the comparison circuit 2Q6, a control circuit 208, and the - forcing circuit 21. The voltage source divider divides a voltage source VDD and outputs a detection voltage Vdet. The detection voltage ^ is • The voltage source Vdd is divided. The bandgap reference voltage generator 2〇4 is used to generate a bandgap reference voltage VBG having a solid value. When the voltage source vDD is reset, the bandgap The reference voltage generator 204 must wait for the voltage source VDD to rise back to a level before generating the bandgap reference voltage Vbg. The comparison circuit 206 is configured to compare the detected voltage vdet with the bandgap reference voltage vBG ' The level of the voltage source vDD is determined. The enable/disable of the comparison circuit 206 is controlled by the control circuit 208. When the bandgap reference voltage Vbg has not been generated, the action of the control circuit 208 is The comparison circuit 206 can be disabled. The gap reference voltage

Client's Docket N〇.:VIT06-0147 TT's Docket No:0608-A41005-TW/Final /Glorious_Tien 1312869 ί 2: The operation of the t-circuit 208 is switched from the comparison circuit 206 to 4 full) The comparison circuit 2G6 . The output moth of the forcing circuit 2 at the comparison circuit 206 is also controlled by the control circuit 208. When the comparison circuit 206 is in the deenergized state, the forcing circuit 210 forces the output voltage A f J ^ u 疋 疋 value of the comparator circuit 206 to prevent the comparison circuit 206 from outputting an erroneous comparison result. Fig. 3 is a view showing an embodiment of the voltage, β^A/original level detecting device of the present invention. The voltage source level detecting device 300 is connected to j

The comparison circuit 302 for intimidation includes a comparator CMP and a first switch q%. The first switch SWi| is connected between the power supply terminal of the comparator CMP and the voltage source VDD of the comparator CMP, and a first control generated by the control circuit 304 is controlled by the control circuit 304. The first switch sw is non-conducting when the side control circuit 304 is de-energized, and is turned on when the control circuit 304 enables the comparison circuit 3〇2. As shown in Fig. 3, the voltage source level pick-up device 3A implements the forcing circuit 21A of Fig. 2 with a second switch SW2. The second switch SW2 is controlled by a second control signal CSz generated by the binary circuit 304. Since the energy gap reference voltage vBG is input to the inversion of the comparator CMP: the input terminal 'and the detection voltage Vdet is input to the non-inverting input of the comparator CMP, the younger switch SW2 must be The comparison circuit 3 〇2 couples its output terminal to a ground terminal (a certain voltage terminal) when the state is in the h state, to ensure that the comparison circuit 302 does not misjudge the detection when the comparison circuit 302 is in the de-energized state. The voltage Vdet is higher than the bandgap reference voltage VBC. FIG. 4 is an embodiment of the control circuit 304, including a capacitor C, a discharge circuit 402, a first inverter Inv, and a second inversion.

Client's Docket N〇.:VIT06-0147 TT's Docket No:〇608-A41005-TW/Final /Glorious Tien 1312869 Inv2. As shown, the first end and the second end of the capacitor C are coupled to the voltage source VDD and the discharge circuit 402, respectively. The discharge circuit 402 is activated after the bandgap reference voltage VBG is generated to generate a discharge current I to discharge the capacitor C. The input end of the first inverter Invi is coupled to the second end of the capacitor C to output the first control signal CS! to control the first switch SWi. When the first control signal CSi is at a high level, the first switch SWi is turned on, and the comparison circuit 302 is enabled; otherwise, the first switch SW! is not turned on, and the comparison circuit 302 is disabled. The input end of the second inverter Inv2 is coupled to the output end of the first inverter Ιην! for inverting the first control signal CS! to generate the second control signal CS2 to control the second switch SW2. When the second control signal CS2 is at a high level, the second switch SW2 is turned on, and vice versa. In the present invention, the above-described discharge current I may decrease as the voltage level of the second terminal of the capacitor C decreases. Fig. 5 is a diagram showing another embodiment of the control circuit 304. The discharge circuit 502 is a current mirror including a first transistor 以及1 and a second transistor M2. The gate of the first transistor is coupled to the drain. The gate voltages of the first and second transistors (M! and M2) are controlled by the bandgap reference voltage VBG and have the same gate-source voltage difference. The second terminal of the second transistor M2 is coupled to the second terminal of the capacitor C. Referring to Fig. 5, when the voltage source VDD is reset but has not yet risen to a level, the bandgap reference voltage Vbg has not yet been generated. Therefore, the discharge circuit 502 has not been turned on, and the discharge current I is zero. At this time, the potential of the second terminal of the capacitor C changes with its first end point, that is, with the voltage source 乂

Client's Docket N〇.:VIT06-0147 TT's Docket No:0608-A41005-TW/Final /Glorious_Tien 1312869 L. Therefore, the potential of the second end of the capacitor c is processed by the first and second inverters Ιη: and Inv2, and the first control signal CSi of low level and the second control signal CS2 of high level are output. . Referring to FIG. 3, by the first and second control signals (CSi and CS2), the control circuit 304 can disable the comparison circuit 302 and force the flag Flag generated by the comparison circuit 302 to be grounded to avoid the comparison. The circuit 302 outputs an erroneous judgment result. Referring to Figure 5, after the voltage source VDD rises back to the level, the bandgap reference voltage VBG is generated, the discharge device 502 is turned on and a discharge is generated. • The current I discharges the capacitor C. Fig. 6 is a graph showing the relationship between the discharge current I and the source-to-source difference VDS_M2 of the second transistor M2. As shown in FIG. 6, when the discharge current I is generated, the potential of the second end of the capacitor C (ie, the 压·source voltage difference VdS_M2 of the second transistor M2) is V〇' the discharge current 1 =1. The potential of the second terminal of the capacitor C (VDS_M2) gradually decreases during the discharge process. As shown in Fig. 6, the discharge current I also gradually decreases, and finally both fall to zero. The discharge process causes the second terminal potential of the capacitor C to be processed by the first and second inverters 11^1 and Inv2, and outputs a first control signal CSi of the high level and a low level. The second control signal cs2. Therefore, the comparison circuit 302 is enabled and the output of the comparison circuit 302 is no longer forced to ground. The comparison circuit 302 is ready for normal operation. FIG. 7 is another embodiment of the control circuit 304. The discharge circuit 702 is an N-type MOS transistor Mn, the gate is coupled to the bandgap reference voltage VBG, and the drain is coupled to the capacitor C. The second end point and its source is grounded. It can be seen from the above embodiment that the discharge circuit of the present invention stops supplying the discharge current after the potential of the second terminal of the capacitor C falls to zero.

Client's Docket N〇.: VIT06-0147 TT's Docket No: 0608-A41005-TW/Final /Glorious_Tien, I312869 i, so the present invention does not require a lot of energy. FIG. 8 is another embodiment of the present invention, wherein the voltage source voltage divider 802 is used by a plurality of resistors (heart and R2 in this embodiment) connected in series between the voltage source vDD and a ground terminal. composition. The invention adopts a simple resistor partial voltage, and the user can easily grasp the relationship between the detection voltage Vdet and the voltage source vdd. In contrast, in the conventional voltage source level detecting device of the first drawing, the resistance value Rcm of the transistor Ms of the detecting voltage generating circuit -04 is difficult to grasp with the change of φ%, which is likely to cause user trouble. FIG. 9 is another embodiment of the present invention, further including a switching device 902 ′ coupled between the voltage source voltage divider 904 and the comparison circuit 906 for when the comparison circuit 906 is in an unenergized state. 'Switching the detection voltage Vdet to a ground terminal for inputting the comparison circuit 906. As shown, the switching device 902 includes a third switch SW3 and a fourth switch SW4. The third switch SW3 is turned on when the comparison circuit 906 is enabled (the first control signal 〇81 is at a high level) for coupling the detection voltage to the comparison circuit 9〇6. The fourth switch SW* is turned on when the comparison circuit 906 is deenergized (the second control signal CS2 is at a high level) for coupling the ground terminal to the comparison circuit 906. Figure 10 is another embodiment of the present invention including multiple sets of comparison circuits (1002 and 1004). The voltage source voltage divider 1〇〇6 of this embodiment outputs two sets of detection voltages (Vdetl and Vdet2), which are input to the comparison circuits 1 〇〇 2 and 1004, respectively. The operation of the comparison circuits 1〇〇2 and 1〇〇4 and the compulsory circuit to which the output terminals are coupled are the same as other embodiments of the present invention. With this embodiment, the user can judge by the flags Flagl and Flag2

Client’s Docket N〇.:VIT06-0147 TT^ Docket No:0608-A41005-TW/Final /Glorious Tien 11 1312869 This voltage source vDD is currently within a certain voltage range. The present invention has been described above with reference to the preferred embodiments thereof, and is not intended to limit the scope of the present invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

Client's Docket N〇.:VIT06-0147 TT's Docket No:0608-A41005-TW/Final /Glorious_Tien 1312869 [Simple diagram of the diagram] Figure 1 is a conventional voltage source level detection device; Figure 2 is the invention FIG. 3 is a schematic diagram of a voltage source level detecting device according to the present invention; FIG. 4 is an embodiment of the control circuit 304; FIG. 5 is another embodiment of the control circuit 304. An embodiment; FIG. 6 is a diagram showing the relationship between the discharge current I and the threshold voltage difference Vds_M2 of the second transistor M2 of FIG. 5, and FIG. 7 is another embodiment of the control circuit 304; An embodiment of the voltage source level detecting device of the present invention; FIG. 9 is an embodiment of the voltage source level detecting device of the present invention; and FIG. 10 is a voltage source level detecting device of the present invention. An embodiment. [Main component symbol description] 100~ conventional voltage source level detecting device; 102~gap reference voltage generator; 104~ detecting voltage generating circuit; 200~voltage source level detecting device; 202~voltage source voltage dividing 204~bandgap reference voltage generator; 206~comparing circuit; 208~control circuit; 210~force circuit; 300~voltage source level detecting device; 302~comparing circuit; 304~control circuit; 402~discharging circuit 502~ discharge circuit; 702~ discharge circuit; 802~voltage source voltage divider; 902~ switching circuit;

Client's Docket N〇.:VIT06-0147 TT5s Docket No:0608-A41005-TW/Final/Glorious Tien 13 1312869 904~voltage source divider; 1002,1004~comparison circuit; C~capacitor; CSi~first control signal 906~ comparison circuit; 1006~voltage source voltage divider; CMP~comparator; CS2~second control signal;

Flag, Flagl, Flag2~ comparison circuit output flag; I~ discharge current;

Inv2 to second inverter;

Mi, M2, and M3 ~ transistor Ri and R2 ~ resistance; SWi ~ first switch; SW3 ~ third switch;

Vbg~gap reference voltage; Ιηνγ first inverter;

Mn~N type MOS semi-transistor SW2~second switch; SW4~fourth switch;

Vdd~ voltage source; vdet, vdetl, vdet2~ detection voltage.

Client’s Docket N〇,:VIT06-0147 TT's Docket No:0608-A41005-TW/Final /Glorious Tien 14

Claims (1)

1312869 X. Patent application scope: 1 · A voltage source level detecting device, which comprises: - a voltage source voltage divider, (4) - a voltage source to generate - a detection voltage; and a gap reference voltage generation ^ at the voltage The source is reset and returns a level to generate a bandgap reference voltage; a comparison circuit compares the detected voltage and the bandgap reference voltage to determine the level of the voltage source; a first control circuit, When the bandgap reference voltage has not been generated, the comparator circuit can be turned off, and after the bandgap reference voltage is generated, the comparator circuit can be converted to enable the comparator circuit; - forcing the circuit, it is difficult for the output of the comparison circuit to be controlled by the control circuit to force the output voltage of the comparison circuit to be a constant value when the control circuit has not enabled the comparison circuit. 2. The voltage source level detecting device of claim 2, wherein the comparing circuit comprises: a further comparator; and a first switch coupled to the power terminal of the comparator and the voltage The source 1 is controlled by the control (four) way. In the above control circuit, the comparison circuit can be non-conducting and turned on when the comparison circuit enables the comparison circuit. 3. The voltage source level detecting device of claim 2, wherein the forcing circuit is a second switch for coupling the comparison when the control circuit has not enabled the comparison circuit The output of the circuit is connected to the constant voltage terminal to provide the constant value. Client's Docket N〇.:VIT06-0147 TT!s Docket No:〇6〇8-A41005-TW/Final /Glorious Tien 15 1312869 4. The voltage source level measuring device as described in claim 3 The control circuit includes: a capacitor, the first end of which is coupled to the voltage source; the discharge device is coupled to the second end of the capacitor, and is activated after the energy gap reference ', to generate a discharge current Discharging the capacitor; : first - inverting 11 'the input terminal 魄 the second end of the f-capacitor controls the first switch by the input-control signal, wherein when the number is high level, the first-switch is turned on Conversely, the second inverter is configured to invert the first control signal to generate a first control and a second switch, wherein the second control signal is at a high level, and the second switch is turned on. Otherwise, it does not conduct. 5^ The voltage source level detection and the discharge current described in item 4 of the patent scope are measured with the calibrated price of the second terminal of the capacitor. The discharge device can be a current mirror, comprising: a first-electrode crystal whose gate is connected with the poleless light; and a second transistor, which is different from the first lightning, wherein the second The crystal has the same gate source and the second and last terminals of the capacitor, and the gate of the second transistor and the first transistor are at the wheel end of the bandgap reference voltage generator. . The remaining horse is connected to 忒7. If the patent application scope is set to item 4, and the 呤 呤 奘罟 T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T _接该=Client's Docket N〇.:VIT06-0147 TT's Docket No:0608-A41005-TW/Final/Glorious Tien 16 1312869 The second end point, and its source is coupled to a ground. 8. The voltage source level detecting device according to claim 1, wherein the voltage source voltage divider is composed of a plurality of resistors connected in series between the voltage source and a ground. 9. The voltage source level detecting device of claim 1 further comprising a switching device for switching the detecting voltage to a ground terminal for input when the control circuit has not enabled the comparing circuit The comparison circuit. 10. The voltage source level detecting device of claim 9, wherein the switching device comprises: a third switch controlled by the control circuit for enabling the comparison circuit at the control circuit And coupling the detection voltage to the comparison circuit, and is non-conducting when the control circuit can disable the comparison circuit; and a fourth switch controlled by the control circuit to enable the comparison at the control circuit In the circuit, the ground terminal is coupled to the comparison circuit, and is non-conductive when the control circuit enables the comparison circuit. Client’s Docket No.:VIT06-0147 TT's Docket No:0608-A41005-TW/Final /Glorious_Tien