CN110635448A - Low quiescent current and have undervoltage protection circuit of dynamic filtering function - Google Patents

Low quiescent current and have undervoltage protection circuit of dynamic filtering function Download PDF

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CN110635448A
CN110635448A CN201911058952.8A CN201911058952A CN110635448A CN 110635448 A CN110635448 A CN 110635448A CN 201911058952 A CN201911058952 A CN 201911058952A CN 110635448 A CN110635448 A CN 110635448A
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power supply
supply voltage
circuit
tube
current
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张允武
禹阔
李冬冬
余思远
吴彩虹
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Wuxi Safe Electronics Co Ltd
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Wuxi Safe Electronics Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
    • H02H3/243—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage for DC systems

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Abstract

The undervoltage protection circuit comprises a power supply voltage positive correlation current generating circuit, a power supply voltage negative correlation current generating circuit, a current comparison circuit and a dynamic filter circuit. The power supply voltage positive and negative correlation current generating circuit is used for generating two paths of currents which are positively correlated and negatively correlated with the power supply voltage respectively, and the current comparison circuit is used for comparing the magnitudes of the two paths of currents to generate an undervoltage protection signal. At the same time, the current inversely related to the supply voltage can be used to realize a dynamic filtering function, i.e. the filtering time increases with the increase of the supply voltage.

Description

Low quiescent current and have undervoltage protection circuit of dynamic filtering function
Technical Field
The invention relates to an undervoltage circuit, in particular to an undervoltage protection circuit with low quiescent current and a dynamic filtering function, and belongs to the field of design of analog integrated circuits (chips).
Background
If the power supply voltage fluctuation of the chip during working is large, an under-voltage protection circuit is usually needed to ensure that the system works stably and normally. Under normal working conditions, the power voltage provided by the power supply system is continuously reduced due to the consumption of the load, when the input voltage is reduced to a certain degree, part of the sub-circuits cannot work normally, and particularly, the digital logic control circuit is easy to have misoperation. In order to prevent this phenomenon, an under-voltage latch circuit needs to be provided. The undervoltage latch circuit is also called low-voltage latch, and when the power supply voltage is reduced to a certain limit value due to some reason, the undervoltage latch circuit can force the chip output to be in a safety state under non-working, and when the power supply voltage is increased to a certain value above the limit value, the chip recovers to work normally. In addition, some chips may operate in an instantaneous large current state for a long time, for example, several amperes, which may increase noise of the power supply, narrow falling pulses may appear in the power supply, and the under-voltage protection circuit may induce the falling of the power supply to turn off the operating state of the chip, but may reduce the operating efficiency of the chip, and thus it is necessary that the under-voltage protection circuit has a certain capability of resisting power supply noise, that is, it is necessary to include an under-voltage filter circuit.
Fig. 1 is a conventional undervoltage protection circuit with filtering function, which is composed of a power supply voltage sampling circuit, a reference voltage circuit, a voltage comparator circuit, and a filter circuit. The sampling circuit generally adopts a resistor voltage division form to obtain a proportional voltage value of a power supply VCC, the reference circuit generally adopts a Zener reference or a band gap reference as a reference voltage of a comparator, the filter circuit generally adopts a filter composed of a current source and a capacitor, or adopts a filter composed of a resistor and a capacitor, the output of the comparator is also used as a feedback signal to control the circuit, so that a negative threshold value is lower than a positive threshold value, the difference value of the negative threshold value and the positive threshold value is a hysteresis voltage, and the output of the undervoltage protection circuit is stabilized to prevent oscillation. When the sampling voltage exceeds the reference voltage, the voltage locking circuit outputs a high-level control signal to allow the chip to normally work; when the sampling voltage is lower than the reference voltage, the undervoltage locking circuit outputs a low-level control signal to turn off the working state of the chip; when the power supply is in descending fluctuation, the comparator outputs negative pulses, if the width of the negative pulses is smaller than the filtering time of the filter circuit, the negative pulses can be filtered, the output OUT is unchanged, and if the width of the negative pulses is larger than the filtering time of the filter circuit, the output OUT can generate a chip turn-off signal.
Fig. 2 is a circuit block diagram of the prior application of "an under-voltage locking circuit with dynamic filtering function" by the applicant 2018108430970 and 2018212126112. The dynamic filter circuit generates a current which is in direct proportion to VCC by sampling a power VCC signal, the current is in inverse proportion to VCC by carrying out a sum operation with a constant current source, and the current which is in inverse proportion to the power voltage is used as a charging current of the filter delay capacitor, so that the dynamic filter circuit is formed. The filtering time of the dynamic filtering circuit is in direct proportion to the power supply voltage, namely the smaller the power supply voltage is, the smaller the filtering time is. Compared with the filter circuit of the traditional undervoltage protection circuit, the filter time of the traditional filter circuit has smaller correlation with the power supply voltage, the low-voltage turn-off speed is slower, and the dynamic filter circuit has the advantages that the state of the power supply voltage can be more accurately reflected, namely, the power supply noise can be more accurately distinguished, the low-voltage state can be more accurately distinguished, and meanwhile, the filter circuit has the power supply noise resistance and the smaller low-voltage turn-off speed, so that the occurrence of chip faults is reduced, and the working efficiency of a chip is improved.
In summary, in order to enhance the power noise resistance of the under-voltage protection circuit, the conventional under-voltage protection circuit is added with an R-C or I-C filter circuit, but the conventional filter circuit sacrifices the low power voltage turn-off speed, so 2018108430970 and 2018212126112 provide a dynamic filter circuit having both noise filtering function and faster low power voltage turn-off speed. In general, the performance of the circuit needs to be compromised with static loss, chip area and the like, and although the performance of the circuit is improved by the above prior art, the static loss and the chip area are sacrificed.
Disclosure of Invention
In order to solve the technical defects existing in the prior art, namely, the contradictory relation existing in the circuit performance, the power consumption and the area, the invention provides the undervoltage protection circuit with low static current and dynamic filtering, wherein the power voltage is applied to two ends of a resistor to form a current positively correlated with the power supply (the current increases along with the increase of the power voltage), then the current positively correlated with the power supply flows through a current-voltage-current conversion circuit to generate a negatively correlated current of the power supply (the current decreases along with the increase of the power voltage), then the positively correlated current and the negatively correlated current are compared, if the positively correlated current is smaller than the negatively correlated current, the power voltage is too low, so that an undervoltage protection signal is generated, and meanwhile, the negatively correlated current of the power supply can be used for realizing the dynamic filtering function, namely, the filtering time increases along with the.
In order to achieve the purpose, the invention adopts the technical scheme that: the utility model provides a low quiescent current just has undervoltage protection circuit of dynamic filtering function which characterized in that: the power supply voltage negative correlation current generating circuit comprises a power supply voltage positive correlation current generating circuit (001), a power supply voltage negative correlation current generating circuit (002), a current comparison circuit (003) and a dynamic filter circuit (004), wherein the current which is generated by the power supply voltage positive correlation current generating circuit (001) and positively correlated with the power supply voltage and the current which is generated by the power supply voltage negative correlation current generating circuit (002) and negatively correlated with the power supply voltage enter the current comparison circuit (003) for comparison to generate an under-voltage protection signal and enter the dynamic filter circuit (004), meanwhile, the current which is negatively correlated with the power supply voltage is used for realizing dynamic filtering in the dynamic filter circuit (004), and the negative correlation current is gradually reduced until the negative correlation current is zero along with the rise of the power supply voltage;
the power supply voltage positive correlation current generation circuit (001) comprises four ports, namely a power supply VCC port, a grounding port, an output port (200) and an output port (201);
the power supply voltage negative correlation current generation circuit (002) comprises six ports, namely a power supply VCC port, a grounding port, an undervoltage protection signal feedforward input port (202), an input port connected with a power supply voltage positive correlation current generation circuit output port (200), an output port (203) and an output port (204);
the current comparison circuit (003) comprises five ports, namely a power supply VCC port, a grounding port, an input port connected with a power supply voltage negative correlation current generation circuit output port (204), an input port connected with a power supply voltage positive correlation current generation circuit output port (201) and an output port (205);
the dynamic filter circuit (004) comprises five ports which are respectively a power supply VCC port, a grounding port, an input port connected with a power supply voltage negative correlation current generating circuit output port (203), an input port connected with a current comparison circuit (003) output port (205) and a filtered undervoltage protection signal output port, and the output ports are simultaneously used as feedforward outputs and connected with a feedforward input port (202) of a power supply voltage negative correlation current generating circuit (002); the filtering time of the dynamic filtering circuit (004) is controlled by the output current (203) of the power supply voltage negative correlation current generating circuit (002), changes along with the change of the power supply voltage, the larger the amplitude of the power supply voltage drop is, the smaller the filtering time is, and the dynamic filtering is realized.
The power supply voltage positive correlation current generation circuit (001) at least comprises a resistor R1, an NMOS tube NM1, an NMOS tube NM2 and an NMOS tube NM3, one end of the resistor R1 is connected with a power supply VCC, the other end of the resistor R1 is connected with the drain and the gate of the NMOS tube NM1, the gate of the NMOS tube NM2 and the gate of the NMOS tube NM3, the source of the NMOS tube NM1, the source of the NMOS tube NM2 and the source of the NMOS tube NM3 are all grounded, the drain of the NMOS tube NM2 serves as an output port (200) of the power supply voltage positive correlation current generation circuit (001), and the drain of the NMOS tube NM3 serves as an output port (201) of the power supply voltage positive correlation current generation circuit (001.
The power supply voltage negative correlation current generating circuit (002) comprises an NMOS tube NM4, a PMOS tube PM1, a PMOS tube PM2, a PMOS tube PM3, a PMOS tube PM4, a resistor R2, a resistor R3 and a resistor R21, the source of the PMOS tube PM1, the source of the PMOS tube PM2, the source of the PMOS tube PM3, the source of the PMOS tube PM4 and one end of the resistor R21 are all connected with a power supply VCC, the other end of the resistor R21 is connected with one end of a resistor R2 and the drain of a PMOS tube PM1, the other end of the resistor R2 is connected with the gate of the NMOS tube NM4 and the output port (200) of the power supply voltage positive correlation current generating circuit (001), the gate of the PMOS tube PM1 is an undervoltage protection signal input port (202), the drain of the PMOS tube PM2 is connected with the gate and the gate of the PMOS tube PM3 and the drain of the PMOS tube PM4, the NMOS tube NM4 is grounded through the resistor R36002, the drain of the PMOS pipe PM4 is the output port (203) of the power supply voltage negative correlation current generating circuit (002).
The current comparison circuit (003) at least comprises an inverter INV1, the input of the inverter INV1 is simultaneously connected with the output port (204) of the power supply voltage negative correlation current generation circuit (002) and the output port (201) of the power supply voltage positive correlation current generation circuit (001), and the output of the inverter INV1 is the output port (205) of the current comparison circuit (003).
The dynamic filter circuit (004) comprises an inverter INV2, an inverter INV3 and a capacitor C1, wherein the input of the inverter INV2 is connected with an output port (205) of a current comparison circuit (003), the power supply end of the inverter INV2 is connected with an output port (203) of a power supply voltage negative correlation current generation circuit (002), the output of the inverter INV2 is connected with the input end of an inverter INV3 and one end of a capacitor C1, the other end of the capacitor C1 is grounded, and the output of the inverter INV3 is the output end of the dynamic filter circuit (004), namely the output port of an undervoltage protection signal.
The NMOS tube NM1, the NMOS tube NM2 and the NMOS tube NM3 in the power voltage positive correlation current generating circuit (001) can be replaced by NPN type BJT tubes Q1, Q2 and Q3 respectively, one end of a resistor R1 is connected with a power VCC, the other end of the resistor R1 is connected with a collector and a base of the NPN type BJT tube Q1, a base of the NPN type BJT tube Q2 and a base of the NPN type BJT tube Q3, an emitter of the NPN type BJT tube Q1, an emitter of the NPN type BJT tube Q2 and an emitter of the NPN type BJT tube Q3 are all grounded, a collector of the NPN type BJT tube Q2 is used as an output port (200) of the power voltage positive correlation current generating circuit (001), and a collector of the NPN type BJT tube Q1 is used as an output port (201) of the.
The power supply voltage positive correlation current generation circuit (001) comprises a resistor R1, an NMOS tube NM1, an NMOS tube NM2 and an NMOS tube NM3, an NMOS tube NM5 and an NMOS tube NM6 can be additionally arranged, an NMOS tube NM5 is arranged between the resistor R1 and the NMOS tube NM1, the drain and the gate of the NMOS tube NM5 are connected with the gate of the NMOS tube NM6 and the other end of the resistor R1, the source of the NMOS tube NM5 is connected with the drain and the gate of the NMOS tube NM1 and the gate of the NMOS tube NM2 and the gate of the NMOS tube NM3, the drain of the NMOS tube NM6 is used as an output port (200) of the power supply voltage positive correlation current generation circuit (001), the source of the NMOS tube NM6 is connected with the drain of the NMOS tube NM 2.
The NMOS transistor NM4 in the power supply voltage negative correlation current generating circuit (002) can be replaced by an NPN type BJT transistor Q4, the other end of the resistor R2 is connected with the base electrode of the NPN type BJT transistor Q1 and the output port (200) of the power supply voltage positive correlation current generating circuit (001), the drain electrode and the grid electrode of the PMOS transistor PM2 are interconnected and connected with the grid electrode of the PMOS transistor PM3, the grid electrode of the PMOS transistor PM4 and the collector electrode of the NPN type BJT transistor Q1, the emitter electrode of the NPN type BJT transistor Q1 is grounded through a resistor R3, and the rest connection relations are unchanged.
The current comparison circuit (003) comprises an inverter INV1, and further comprises a PMOS tube PM5, a PMOS tube PM6, an NMOS tube NM7 and an NMOS tube NM8, wherein the source of the PMOS tube PM5 and the source of the PMOS tube PM6 are connected with a power supply VCC, the gate of the PMOS tube PM5 and the gate of the PMOS tube PM6 are interconnected and connected with an output port (204) of a power supply voltage negative correlation current generation circuit (002), the gate of the NMOS tube NM7 and the gate of the NMOS tube NM8 are interconnected and connected with an output port (201) of a power supply voltage positive correlation current generation circuit (001), the source of the NMOS tube NM7 and the source of the NMOS tube NM8 are grounded, the drain of the PMOS tube PM6 is connected with the drain of the NMOS tube NM8 and the input end of the inverter INV1, and the output of the inverter INV1 is the output port (205) of.
The invention has the advantages and beneficial effects that:
(1) compared with the prior applications 2018108430970 and 2018212126112 of the applicant, the invention adopts a brand new circuit structure, the structure of the invention does not comprise an independent reference circuit and a sampling circuit, but the reference circuit and the sampling circuit are arranged in other circuit modules, a power supply positive correlation current generating circuit and a power supply negative correlation current generating circuit which have lower power consumption and more simplified structures are adopted, and the original complex voltage comparator circuit is replaced by a simple current comparator circuit, so that the invention has higher response speed, particularly has fast turn-off speed under low power supply voltage, and can avoid the occurrence of faults.
(2) The dynamic filter circuit in the prior application of the applicant needs other circuit structures except the delay module to realize the dynamic filter function, but the filter circuit only comprises the delay module, a dynamic current source needed by the delay module is from a power supply negative correlation current generating circuit, the power supply negative correlation current is used as a reference comparison current and a filter charging current, and the current of the power supply negative correlation current is reduced to zero after the power supply voltage rises to a certain value, so that the same dynamic filter function as the prior application can be realized without an additional circuit structure.
(3) From the aspect of static power consumption, the reference circuit, the adopted circuit, the comparator and the dynamic filter circuit in the prior application all generate static power consumption, and the static power consumption in the circuit structure is mainly generated by the power supply positive correlation current generating circuit, so that compared with the prior art, the circuit structure has the advantages of low whole static current, small number of used devices, small layout area and chip cost saving.
Drawings
FIG. 1 is a block diagram of a conventional undervoltage protection circuit;
FIG. 2 is an under-voltage lockout circuit with dynamic filtering capability for applicants' 2018108430970 and 2018212126112;
FIG. 3 is a block diagram of the undervoltage protection circuit with low quiescent current and dynamic filtering of the present invention;
FIG. 4 is a circuit diagram of the undervoltage protection circuit with low quiescent current and dynamic filtering of the present invention;
FIG. 5 is a circuit diagram of an under-voltage protection circuit of FIG. 4 in which the positive correlation current generating circuit and the negative correlation current generating circuit adopt another implementation circuit;
FIG. 6 is a circuit diagram of an under-voltage protection circuit of FIG. 4, in which another implementation circuit is adopted for the positive correlation current generation circuit;
FIG. 7 is a circuit diagram of an under-voltage protection circuit of the current comparison circuit of FIG. 4 with another implementation;
FIG. 8 is a comparison of current versus supply voltage and filter time versus supply voltage for the present invention and comparison to a conventional configuration;
FIG. 9 is a comparison of quiescent current and layout area of the present invention versus conventional structures and prior art patents;
fig. 10 is an operation waveform of the undervoltage protection circuit of the present invention.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, the examples given are intended to illustrate the invention and are not intended to limit the scope of the invention.
Referring to fig. 3, the undervoltage protection circuit with low quiescent current and dynamic filtering of the present invention comprises a power positive correlation current generation circuit (001), a power negative correlation current generation circuit (002), a current comparison circuit (003) and a dynamic filtering circuit (004). The power supply positive correlation current generation circuit (001) outputs two current signals 200 and 201 which are respectively connected with the power supply negative correlation current generation circuit (002) and the current comparison circuit (003), the power supply negative correlation current generation circuit (002) outputs two current signals 204 and 203 which are respectively connected with the current comparison circuit (003) and the dynamic filter circuit (004), the output control signal 205 of the current comparison circuit (003) controls the dynamic filter circuit (004), and the output of the dynamic filter circuit (004) is fed back to the power supply negative correlation current generation circuit (002).
The power supply voltage positive correlation current generating circuit (001) comprises four ports, namely a power supply VCC port, a grounding port and two current output ports 200 and 201. The power supply voltage negative correlation current generating circuit (002) comprises six ports, namely a power supply VCC port, a grounding port, an undervoltage protection signal feedforward input port 202, an input port connected with a power supply voltage positive correlation current generating circuit current output port 200, and two current output ports 203 and 204. The current comparison circuit (003) includes five ports, which are a power VCC port, a ground port, an input port connected to the power-supply-voltage negative-correlation-current generation circuit current output port 204, an input port connected to the power-supply-voltage positive-correlation-current generation circuit current output port 201, and a control signal output port 205. The dynamic filter circuit (004) comprises five ports, namely a power supply VCC port, a grounding port, an input port connected with a power supply voltage negative correlation current generation circuit current output port 203, an input port connected with a current comparison circuit (003) control signal output port 205 and a filtered undervoltage protection signal output port, wherein the output ports are simultaneously used as feedforward outputs and connected with a feedforward input port 202 of a power supply voltage negative correlation current generation circuit (002).
Referring to fig. 4, the power supply positive correlation current generation circuit (001) is composed of NMOS transistors NM1, NM2, NM3 and a resistor R1, converts the power supply VCC into a current approximately proportional to VCC through R1 and NM1, and outputs two current signals to the power supply negative correlation current generation circuit (002) and the current comparison circuit (003) respectively through a current mirror. The power supply negative correlation current generating circuit (002) is composed of PMOS tubes PM 1-PM 4, an NMOS tube NM4 and resistors R2, R21 and R3, firstly, a current 200 is converted into a voltage signal through resistors R2 and R21, the voltage signal is reduced along with the increase of VCC, then the voltage signal is converted into a current signal through the action of NM4 and R3, the current is reduced along with the increase of the power supply VCC, and finally, two paths of currents 204 and 203 are output to a current comparison circuit (003) and a filter circuit (004) respectively through a current mirror. The current comparison circuit (003) is composed of only one inverter INV1, and generates the under-voltage signal 204 by comparing the currents 201 and 204, when the current 201 is greater than 204 (at this time, it is assumed that NM3 and PM3 both operate in the saturation region), i.e. the power supply VCC is high, the input terminal of the INV1 is in the discharge state until it is low, the output 205 is high, otherwise, when 201 is less than 204, the output 205 is low. The dynamic filter circuit (004) is composed of inverters INV2 and INV3 and a capacitor C1. The filtering time of the dynamic filtering circuit (004) is controlled by the output current 203 of the power supply voltage negative correlation current generating circuit (002), and changes along with the change of the power supply voltage, the larger the amplitude of the power supply voltage drop is, the smaller the filtering time is, and the dynamic filtering is realized. The power supply positive correlation current generation circuit (001) outputs two current signals 200 and 201 which are respectively connected with the power supply negative correlation current generation circuit (002) and the current comparison circuit (003), the power supply negative correlation current generation circuit (002) outputs two current signals 204 and 203 which are respectively connected with the current comparison circuit (03) and the dynamic filter circuit (004), the output control signal 205 of the current comparison circuit (003) controls the dynamic filter circuit (004), and the output of the dynamic filter circuit (004) is fed back to the power supply negative correlation current generation circuit (002).
Assuming that the width-to-length ratios of NM1, NM2, NM3 are the same and the width-to-length ratios of PM2, PM3, and PM4 are the same, port 200201, 203 and 204 (assuming that the currents of the ports 200, 201, 203 and 204 are I respectively)200、I201、I203、I204The gate-source voltages of NM1 and NM4 are V respectivelyGS1、VGS4)：
Figure BDA0002257340370000071
Figure BDA0002257340370000072
When I is201<I204Is an under-voltage state, and when I201>I204Is not under-voltage state, therefore, order I201＝I204The undervoltage threshold voltage (V) can be obtainedUV) Comprises the following steps:
Figure BDA0002257340370000073
time t of filteringfltIs (let the input threshold voltage of the inverter INV2 be VTH)：
Figure BDA0002257340370000074
As can be seen from the above formula, the power supply positive correlation current I200Increase as VCC increases, if R2>R1, obtaining power supply negative correlation current I203，I203Decreases as the power supply VCC increases; undervoltage threshold and VGS1、VGS4In relation to the resistance ratio, the desired undervoltage threshold can be obtained by adjusting the resistance size and ratio, and the partial temperature drift can be balanced, and R21 can be used for adjusting the difference value of the undervoltage falling threshold and the rising threshold, namely the hysteresis voltage; due to VTHIncreases as VCC increases, while I203Decreases as VCC increases, therefore, the filter time tfltIncreasing as VCC increases, a dynamic filtering function is implemented.
Referring to fig. 5, unlike fig. 4, a power supply positive correlation current generating circuit(001) The NMOS transistors NM1, NM2 and NM3 in the power supply negative correlation current generation circuit (002) can be replaced by NPN-type BJT transistors Q1, Q2 and Q3, and the NM4 in the power supply negative correlation current generation circuit (002) can be replaced by a BJT transistor Q4. Let Q1, Q2 and Q3 have the same emitter area and number, PM2, PM3 and PM4 have the same width-to-length ratio, and Q1 and Q4 have base-emitter voltages VBE1And VBE4Can obtain a current I200、I201、I203、I204Magnitude, undervoltage threshold VUV：
Figure BDA0002257340370000081
Figure BDA0002257340370000082
According to the above formula, the desired current and undervoltage threshold voltage can be obtained by adjusting the resistance, and a dynamic filtering function can be obtained at the same time.
Referring to fig. 6, the difference from fig. 4 is that NM5 and NM6 transistors are added to the power supply positive correlation current generating circuit (001). Assuming that the width-to-length ratios of NM1, NM2, NM3, NM5 and NM6 are the same, and the width-to-length ratios of PM2, PM3 and PM4 are the same, the magnitudes of the currents of the ports 200, 201, 203 and 204 are (assuming that the currents of the ports 200, 201, 203 and 204 are I, respectively)200、I201、I203、I204The gate-source voltages of NM1 and NM4 are V respectivelyGS1、VGS4)：
Figure BDA0002257340370000084
Figure BDA0002257340370000085
Let I201＝I204The undervoltage threshold voltage (V) can be obtainedUV) Comprises the following steps:
Figure BDA0002257340370000086
time t of filteringfltIs (let the input threshold voltage of the inverter INV2 be VTH)：
Figure BDA0002257340370000091
As can be seen from the above formula, the power supply positive correlation current I200Increase as VCC increases, if R2>R1, obtaining power supply negative correlation current I203，I203Decreases as the power supply VCC increases; undervoltage threshold and VGS1、VGS4In relation to the resistance ratio, the desired undervoltage threshold can be obtained by adjusting the resistance size and ratio, and the partial temperature drift can be balanced, and R21 can be used for adjusting the difference value of the undervoltage falling threshold and the rising threshold, namely the hysteresis voltage; due to VTHIncreases as VCC increases, while I203Decreases as VCC increases, therefore, the filter time tfltIncreasing as VCC increases, a dynamic filtering function is implemented.
In fig. 4, 5, and 6, the power supply positive correlation current generation circuit (001) and the power supply negative correlation current generation circuit (002) may be replaced at the same time or at different times.
As shown in fig. 7, the current comparison circuit (003) in fig. 4, 5 and 6 is different from the current comparison circuit (003) in fig. 4, 5 and 6 in that only one inverter INV1 is provided, the pull-up current and the pull-down current of the input branch determine the output signal level of the inverter INV1, the power supply negative correlation current 204 decreases with the increase of VCC, the power supply positive correlation current 201 increases with the increase of VCC, and the undervoltage protection signal is generated by comparing the magnitudes of the power supply negative correlation current and the power supply positive correlation current. Compared with fig. 4, 5 and 6, PMOS transistors PM5 and PM6 and NMOS transistors NM7 and NM8 are added in fig. 7, and the working principle is as follows: the current 201 is proportionally copied by current mirrors PM5 and PM6 (the proportion is the ratio of width to length of PM5 to PM 6), the current 204 is proportionally copied by current mirrors NM7 and NM8, the copied currents commonly flow into the input end of an inverter INV1, if the copy current of 201 is larger than the copy current of 204, the input end of INV1 is at high level, the output 205 is at low level, and otherwise, the output 205 is at high level. The purpose of adding a current mirror is to prevent cross talk between signals, such as the signal at the input of INV1, from interfering with the currents 201 and 204, but doing so will increase some of the quiescent current.
Referring to fig. 8, the operating waveform of the output signal of the undervoltage protection circuit with low quiescent current and dynamic filtering according to the present invention is shown as varying with the supply Voltage (VCC). Graph a shows the positive correlation current I201And negative correlation current I204With the change curve of the power VCC, the VCC corresponding to the intersection point of the two is the undervoltage threshold voltage (V)CCUV) (ii) a The graph b is a curve of the variation of the undervoltage filtering time along with VCC, and compared with the traditional circuit structure, the filter time variation slope of the invention is larger, so the undervoltage filtering effect is better.
Fig. 9 shows that in comparison with the prior art, the static power consumption of fig. 9(a) and the layout area of fig. 9(b) are much better than the prior art.
Fig. 10 is a working waveform of the under-voltage protection circuit of the present invention varying with the supply Voltage (VCC). The result shows that the undervoltage protection circuit can realize the output of undervoltage signals by utilizing the positive and negative related current of the power supply voltage when the power supply voltage VCC exceeds the positive undervoltage threshold value (V)CCUV+) When the voltage is low, the undervoltage protection signal is output to be a high level; if the supply voltage VCC is below the reverse undervoltage threshold (V) for some reasonCCUV-) the undervoltage protection signal is output as low level, prohibiting the subsequent circuit from working, avoiding the chip function abnormality when the power supply voltage changes slightly.
The above description is only a preferred example of the present invention and is not limited to the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. The utility model provides a low quiescent current just has undervoltage protection circuit of dynamic filtering function which characterized in that: the power supply voltage negative correlation current generating circuit comprises a power supply voltage positive correlation current generating circuit (001), a power supply voltage negative correlation current generating circuit (002), a current comparison circuit (003) and a dynamic filter circuit (004), wherein the current which is generated by the power supply voltage positive correlation current generating circuit (001) and positively correlated with the power supply voltage and the current which is generated by the power supply voltage negative correlation current generating circuit (002) and negatively correlated with the power supply voltage enter the current comparison circuit (003) for comparison to generate an under-voltage protection signal and enter the dynamic filter circuit (004), meanwhile, the current which is negatively correlated with the power supply voltage is used for realizing dynamic filtering in the dynamic filter circuit (004), and the negative correlation current is gradually reduced until the negative correlation current is zero along with the rise of the power supply voltage;
the power supply voltage positive correlation current generation circuit (001) comprises four ports, namely a power supply VCC port, a grounding port, an output port (200) and an output port (201);
the power supply voltage negative correlation current generation circuit (002) comprises six ports, namely a power supply VCC port, a grounding port, an undervoltage protection signal feedforward input port (202), an input port connected with a power supply voltage positive correlation current generation circuit output port (200), an output port (203) and an output port (204);
the current comparison circuit (003) comprises five ports, namely a power supply VCC port, a grounding port, an input port connected with a power supply voltage negative correlation current generation circuit output port (204), an input port connected with a power supply voltage positive correlation current generation circuit output port (201) and an output port (205);
the dynamic filter circuit (004) comprises five ports which are respectively a power supply VCC port, a grounding port, an input port connected with a power supply voltage negative correlation current generating circuit output port (203), an input port connected with a current comparison circuit (003) output port (205) and a filtered undervoltage protection signal output port, and the output ports are simultaneously used as feedforward outputs and connected with a feedforward input port (202) of a power supply voltage negative correlation current generating circuit (002); the filtering time of the dynamic filtering circuit (004) is controlled by the output current (203) of the power supply voltage negative correlation current generating circuit (002), changes along with the change of the power supply voltage, the larger the amplitude of the power supply voltage drop is, the smaller the filtering time is, and the dynamic filtering is realized.
2. The low quiescent current, dynamic filtering brown-out protection circuit of claim 1, wherein: the power supply voltage positive correlation current generation circuit (001) at least comprises a resistor R1, an NMOS tube NM1, an NMOS tube NM2 and an NMOS tube NM3, one end of the resistor R1 is connected with a power supply VCC, the other end of the resistor R1 is connected with the drain and the gate of the NMOS tube NM1, the gate of the NMOS tube NM2 and the gate of the NMOS tube NM3, the source of the NMOS tube NM1, the source of the NMOS tube NM2 and the source of the NMOS tube NM3 are all grounded, the drain of the NMOS tube NM2 serves as an output port (200) of the power supply voltage positive correlation current generation circuit (001), and the drain of the NMOS tube NM3 serves as an output port (201) of the power supply voltage positive correlation current generation circuit.
3. The low quiescent current, dynamic filtering brown-out protection circuit of claim 1, wherein: the power supply voltage negative correlation current generating circuit (002) comprises an NMOS tube NM4, a PMOS tube PM1, a PMOS tube PM2, a PMOS tube PM3, a PMOS tube PM4, a resistor R2, a resistor R3 and a resistor R21, the source of the PMOS tube PM1, the source of the PMOS tube PM2, the source of the PMOS tube PM3, the source of the PMOS tube PM4 and one end of the resistor R21 are all connected with a power supply VCC, the other end of the resistor R21 is connected with one end of a resistor R2 and the drain of a PMOS tube PM1, the other end of the resistor R2 is connected with the gate of the NMOS tube NM4 and the output port (200) of the power supply voltage positive correlation current generating circuit (001), the gate of the PMOS tube PM1 is an undervoltage protection signal input port (202), the drain of the PMOS tube PM2 is connected with the gate and the gate of the PMOS tube PM3 and the drain of the PMOS tube PM4, the NMOS tube NM4 is grounded through the resistor R36002, the drain of the PMOS pipe PM4 is the output port (203) of the power supply voltage negative correlation current generating circuit (002).
4. The low quiescent current, dynamic filtering brown-out protection circuit of claim 1, wherein: the current comparison circuit (003) at least comprises an inverter INV1, the input of the inverter INV1 is simultaneously connected with the output port (204) of the power supply voltage negative correlation current generation circuit (002) and the output port (201) of the power supply voltage positive correlation current generation circuit (001), and the output of the inverter INV1 is the output port (205) of the current comparison circuit (003).
5. The low quiescent current, dynamic filtering brown-out protection circuit of claim 1, wherein: the dynamic filter circuit (004) comprises an inverter INV2, an inverter INV3 and a capacitor C1, wherein the input of the inverter INV2 is connected with an output port (205) of a current comparison circuit (003), the power supply end of the inverter INV2 is connected with an output port (203) of a power supply voltage negative correlation current generation circuit (002), the output of the inverter INV2 is connected with the input end of an inverter INV3 and one end of a capacitor C1, the other end of the capacitor C1 is grounded, and the output of the inverter INV3 is the output end of the dynamic filter circuit (004), namely the output port of an undervoltage protection signal.
6. The low quiescent current, dynamic filtering brown-out protection circuit of claim 2, wherein: in the power supply voltage positive correlation current generation circuit (001), an NMOS tube NM1, an NMOS tube NM2 and an NMOS tube NM3 are respectively replaced by NPN-type BJT tubes Q1, Q2 and Q3, one end of a resistor R1 is connected with a power supply VCC, the other end of the resistor R1 is connected with a collector and a base of the NPN-type BJT tube Q1, a base of the NPN-type BJT tube Q2 and a base of the NPN-type BJT tube Q3, an emitter of the NPN-type BJT tube Q1, an emitter of the NPN-type BJT tube Q2 and an emitter of the NPN-type BJT tube Q3 are all grounded, a collector of the NPN-type BJT tube Q2 is used as an output port (200) of the power supply voltage positive correlation current generation circuit (001), and a collector of the NPN-type BJT tube Q1.
7. The low quiescent current, dynamic filtering brown-out protection circuit of claim 2, wherein: the power supply voltage positive correlation current generation circuit (001) comprises a resistor R1, an NMOS tube NM1, an NMOS tube NM2 and an NMOS tube NM3, an NMOS tube NM5 and an NMOS tube NM6 are additionally arranged, an NMOS tube NM5 is arranged between the resistor R1 and the NMOS tube NM1, the drain and the gate of the NMOS tube NM5 are connected with the gate of the NMOS tube NM6 and the other end of the resistor R1, the source of the NMOS tube NM5 is connected with the drain and the gate of the NMOS tube NM1 and the gate of the NMOS tube NM2 and the gate of the NMOS tube NM3, the drain of the NMOS tube NM6 is used as an output port (200) of the power supply voltage positive correlation current generation circuit (001), the source of the NMOS tube NM6 is connected with the drain of the NMOS tube NM2, and.
8. The low quiescent current, dynamic filtering brown-out protection circuit of claim 3, wherein: an NMOS tube NM4 in the power supply voltage negative correlation current generating circuit (002) is replaced by an NPN type BJT tube Q4, the other end of a resistor R2 is connected with the base electrode of the NPN type BJT tube Q1 and the output port (200) of the power supply voltage positive correlation current generating circuit (001), the drain electrode and the grid electrode of the PMOS tube PM2 are interconnected and connected with the grid electrode of the PMOS tube PM3, the grid electrode of the PMOS tube PM4 and the collector electrode of the NPN type BJT tube Q1, the emitter electrode of the NPN type BJT tube Q1 is grounded through a resistor R3, and the other connection relations are unchanged.
9. The low quiescent current, dynamic filtering brown-out protection circuit of claim 4, wherein: the current comparison circuit (003) comprises an inverter INV1, and is additionally provided with a PMOS tube PM5, a PMOS tube PM6, an NMOS tube NM7 and an NMOS tube NM8, wherein the source of the PMOS tube PM5 and the source of the PMOS tube PM6 are both connected with a power supply VCC, the gate of the PMOS tube PM5 is interconnected with the gate of the PMOS tube PM6 and connected with the output port (204) of the power supply voltage negative correlation current generation circuit (002), the gate of the NMOS tube NM7 is interconnected with the gate of the NMOS tube NM8 and connected with the output port (201) of the power supply voltage positive correlation current generation circuit (001), the source of the NMOS tube NM7 and the source of the NMOS tube NM8 are both grounded, the drain of the PMOS tube PM6 is connected with the drain of the NMOS tube NM8 and the input end of the inverter INV1, and the output of the inverter INV1 is the output port.
CN201911058952.8A 2019-11-01 2019-11-01 Low quiescent current and have undervoltage protection circuit of dynamic filtering function Pending CN110635448A (en)

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CN201911058952.8A CN110635448A (en) 2019-11-01 2019-11-01 Low quiescent current and have undervoltage protection circuit of dynamic filtering function

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4240111A4 (en) * 2020-11-04 2024-04-03 Suzhou Opple Lighting Co., Ltd. Control circuit and lighting device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4240111A4 (en) * 2020-11-04 2024-04-03 Suzhou Opple Lighting Co., Ltd. Control circuit and lighting device

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