CN116540821A - Temperature protection circuit and method for low-voltage-drop voltage stabilizer - Google Patents
Temperature protection circuit and method for low-voltage-drop voltage stabilizer Download PDFInfo
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- CN116540821A CN116540821A CN202310502020.8A CN202310502020A CN116540821A CN 116540821 A CN116540821 A CN 116540821A CN 202310502020 A CN202310502020 A CN 202310502020A CN 116540821 A CN116540821 A CN 116540821A
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
- G05F1/567—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for temperature compensation
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Abstract
The invention discloses a temperature protection circuit and a method of a low-voltage-drop voltage stabilizer, wherein the circuit is applied to the low-voltage-drop voltage stabilizer, and the temperature protection circuit is used for collecting first voltage through a first input end, collecting second voltage through a second input end and outputting a first output signal through a first output end; the first output signal is a low voltage signal or a high voltage signal; the first voltage is a reference voltage; the second voltage is inversely proportional to absolute temperature; the low-voltage-drop voltage stabilizer is used for outputting a first output voltage through an output end of the low-voltage-drop voltage stabilizer according to a first output signal acquired by the first input end and a first voltage acquired by the second input end; if the first output signal is a low voltage signal, the low-voltage-drop voltage stabilizer stops working; if the first output signal is a high-voltage signal, the low-voltage-drop voltage stabilizer works normally to output the first output voltage, and the over-temperature response speed of the circuit is improved on the basis of simple structure of the temperature protection circuit.
Description
Technical Field
The present invention relates to the field of integrated circuits, and more particularly, to a temperature protection circuit and method for a low dropout voltage regulator.
Background
The low dropout voltage regulator (LDO) serving as a power management chip has the characteristics of low power consumption, small size, simple circuit structure and the like. The basic principle of the low-voltage drop voltage stabilizer is as follows: a reference voltage independent of the supply voltage and the temperature is generated by the bandgap reference, and an error amplifier compares a feedback signal of the reference voltage and the output voltage and transmits an error amplification to the gate of a regulating transistor (regulating tube). The adjusting tube is responsible for driving the load, and if the power consumption of the adjusting tube is too high, the temperature is too high, and the chip may be damaged thermally. The existing temperature protection circuit applied to the low-voltage-drop voltage stabilizer has the problems of complex structure, large occupied chip area and low over-temperature response speed.
Disclosure of Invention
The invention provides a temperature protection circuit of a low-voltage drop voltage stabilizer, which is used for simplifying the temperature protection circuit and improving the over-temperature response speed.
In order to simplify a temperature protection circuit and improve the over-temperature response speed, the invention provides a temperature protection circuit of a low-voltage-drop voltage stabilizer, which is applied to the low-voltage-drop voltage stabilizer, wherein a first input end of the low-voltage-drop voltage stabilizer is connected with a first output end of the temperature protection circuit; the first voltage is connected to the second input end of the low-voltage-drop voltage stabilizer;
the temperature protection circuit includes: a differential input comparator, a schmitt trigger, and a level shifter;
the first sampling end of the differential input comparator is used as the first input end of the temperature protection circuit, the second sampling end of the differential input comparator is used as the second input end of the temperature protection circuit, the output end of the differential input comparator is connected with the input end of the Schmitt trigger, the output end of the Schmitt trigger is connected with the input end of the level shifter, and the output end of the level shifter is used as the first output end of the temperature protection circuit;
the temperature protection circuit is used for collecting first voltage through a first input end, collecting second voltage through a second input end and outputting a first output signal through a first output end; the first output signal is a low voltage signal or a high voltage signal; the first voltage is a reference voltage; the second voltage is inversely proportional to absolute temperature;
the low-voltage-drop voltage stabilizer is used for outputting a first output voltage through an output end of the low-voltage-drop voltage stabilizer according to a first output signal acquired by a first input end and a first voltage acquired by a second input end; if the first output signal is a low voltage signal, the low-voltage-drop voltage stabilizer stops working; and if the first output signal is a high-voltage signal, the low-voltage-drop voltage stabilizer works normally and outputs a first output voltage.
Further, the differential input comparator includes: a PMOS current source, a PMOS differential input pair, and an active current mirror load;
the PMOS differential input pair includes a first differential element and a second differential element; taking a grid electrode of a first differential element as a first sampling end of a differential input comparator; the second sampling end of the differential input comparator is connected with the grid electrode of the second differential element; the source electrode of the first differential element and the source electrode of the second differential element are connected with the drain electrode of the PMOS current source; the grid electrode of the PMOS current source is connected with bias voltage, and the source electrode of the PMOS current source is connected with a first power supply;
the active current mirror load includes a first load and a second load; the drain electrode of the first load is connected with the drain electrode of the first differential element; the drain electrode of the first load and the grid electrode of the first load are connected with the grid electrode of the second load; the drain electrode of the second load is connected with the drain electrode of the second differential element and is used as the output end of the differential input comparator; the sources of the first load and the second load are grounded.
Further, the output end of the differential input comparator is connected with the input end of the schmitt trigger through a first connection circuit, specifically:
the first connection circuit comprises a common source amplifier and a first transistor;
the common source stage amplifier includes a second transistor and a third transistor; the grid electrode of the second transistor is connected with bias voltage, and the source electrode of the second transistor is connected with a first power supply; the grid electrode of the third transistor and the drain electrode of the second load are connected with the drain electrode of the second differential element; the source electrode of the third transistor and the source electrode of the first transistor are grounded; the drain electrode of the second transistor and the drain electrode of the third transistor are connected with the drain electrode of the first transistor and the input end of the Schmitt trigger.
Further, the schmitt trigger comprises a first PMOS, a first NMOS, a second PMOS, a second NMOS, a third PMOS and a third NMOS;
the sources of the first PMOS, the second PMOS and the third PMOS are connected to a first power supply; the sources of the first NMOS, the second NMOS and the third NMOS are all grounded;
the grid electrode of the first PMOS is connected with the grid electrode of the first NMOS and is used as the input end of the Schmitt trigger; the drain electrode of the first PMOS, the drain electrode of the first NMOS, the grid electrode of the first transistor, the drain electrode of the second PMOS, the drain electrode of the second NMOS, the grid electrode of the third PMOS and the grid electrode of the third NMOS are connected; the grid electrode of the second PMOS, the grid electrode of the second NMOS, the drain electrode of the third PMOS and the drain electrode of the third NMOS are connected and serve as the output end of the Schmitt trigger.
Further, the level shifter includes: fourth PMOS, fourth NMOS, fifth PMOS, fifth NMOS, sixth PMOS, and sixth NMOS;
the sources of the fourth PMOS, the fifth PMOS and the sixth PMOS are connected to a first power supply; the sources of the fourth NMOS, the fifth NMOS and the sixth NMOS are all grounded;
the grid electrode of the fourth PMOS, the grid electrode of the fourth NMOS and the grid electrode of the sixth NMOS are connected and serve as input ends of the level shifter; the drain electrode of the fourth PMOS, the drain electrode of the fourth NMOS and the grid electrode of the fifth NMOS are connected; the drain electrode of the fifth NMOS, the drain electrode of the fifth PMOS and the grid electrode of the sixth PMOS are connected; the grid electrode of the fifth PMOS, the drain electrode of the sixth PMOS and the drain electrode of the sixth NMOS are connected and serve as output ends of the level shifter.
Further, the second voltage is generated by a v_ctat generation circuit;
the V_CTAT generation circuit specifically comprises: a reference current source, a resistor and a bipolar transistor;
the output end of the reference current source and one end of the resistor are connected with the drain electrode of the bipolar transistor; the other end of the resistor is connected with the grid electrode of the bipolar transistor; the source electrode of the bipolar transistor is grounded; the base-emitter voltage of the bipolar transistor is taken as a second voltage, which is inversely proportional to absolute temperature.
Further, the low dropout regulator includes: the error amplifier, the adjusting tube, the first feedback resistor, the second feedback resistor, the first pull-up device and the second pull-up device;
the source electrode of the first pull-up device is connected with a first power supply, the drain electrode of the first pull-up device is connected with the source electrode of the second pull-up device, the drain electrode of the second pull-up device is connected with the output end of the error amplifier, the grid electrode of the first pull-up device is connected with the grid electrode of the second pull-up device and is used as a first input end of the low-voltage drop-out voltage stabilizer, and the first input end is used for collecting a first output signal of a first output end of the temperature protection circuit;
the source electrode of the adjusting tube is connected with a first power supply, the drain electrode of the adjusting tube is used as the output end of the low-voltage-drop voltage stabilizer, and the drain electrode of the adjusting tube is connected with one end of a first feedback resistor; the other end of the first feedback resistor is connected with one end of a second feedback resistor, and the other end of the second feedback resistor is grounded;
and the inverting input end of the error amplifier is used as the second input end of the low-voltage-drop voltage stabilizer, the first voltage is connected into the inverting input end, the non-inverting input end of the error amplifier is connected into the feedback voltage generated by the second feedback resistor, and the output end of the error amplifier, the grid electrode of the adjusting tube and the drain electrode of the second pull-up device are connected.
Further, the low-voltage drop voltage stabilizer stops working after receiving the low-voltage signal, specifically:
when the grid electrode of the first pull-up device and the grid electrode of the second pull-up device receive low voltage signals output by the temperature protection circuit, the first pull-up device and the second pull-up device are conducted to generate pull-up current; and the pull-up current adjusts the grid voltage of the adjusting tube to be the same as the first power supply voltage, so that the adjusting tube is closed, and the low-voltage-drop voltage stabilizer stops working.
Further, the low dropout voltage regulator normally works after receiving the high voltage signal, specifically:
when the grid electrode of the first pull-up device and the grid electrode of the second pull-up device receive the high voltage signals output by the temperature protection circuit, the first pull-up device and the second pull-up device are cut off, the adjusting tube is conducted, and the low-voltage-drop voltage stabilizer works normally.
As a preferable scheme, the temperature protection circuit is constructed by the differential input comparator, the Schmitt trigger and the level shifter which are sequentially connected, and the first voltage and the second voltage are compared by the differential input comparator to judge whether the adjusting tube is over-heated or not. And if the temperature is over, controlling the differential input comparator to output high voltage. The high voltage output by the differential input comparator passes through the Schmitt trigger to reduce the interference of input noise and quickly overturn at the output end, and the Schmitt trigger outputs the high voltage; the level shifter inverts the voltage to output low voltage after receiving the high voltage output by the Schmitt trigger; the low voltage output by the level shifter is input into the low-dropout voltage regulator to stop the operation. Compared with the existing temperature protection circuit, the temperature protection circuit provided by the invention has the advantages that the structure is simpler, the occupied chip area is small, and the judgment and response on whether the adjusting tube is over-temperature can be rapidly carried out through the voltage comparison of the differential input comparator and the voltage processing of the Schmidt trigger and the level shifter, so that the over-temperature response speed of the circuit is improved.
Correspondingly, the invention also provides a temperature protection method of the low-dropout voltage regulator, which comprises the following steps:
judging whether the temperature of the adjusting tube is higher than a preset temperature or not through the first voltage and the second voltage acquired by the temperature protection circuit of the low-voltage drop voltage stabilizer;
if the second voltage is lower than the first voltage, determining that the temperature of the adjusting tube is higher than a preset temperature, and controlling the temperature protection circuit to output a low voltage signal so that the low voltage drop voltage stabilizer stops working after receiving the low voltage signal;
if the second voltage is not lower than the first voltage, determining that the temperature of the adjusting tube is not higher than the preset temperature, and controlling the temperature protection circuit to output a high-voltage signal so that the low-voltage-drop voltage stabilizer can work normally after receiving the low-voltage signal.
As a preferred scheme, the invention can rapidly judge and respond to whether the temperature of the adjusting tube is higher than the preset temperature by comparing the voltage of the differential input comparator of the temperature protection circuit of the low-voltage-drop voltage stabilizer and processing the voltage of the Schmitt trigger and the level shifter, and control the working state of the low-voltage-drop voltage stabilizer, and stop working when the temperature of the adjusting tube is higher than the preset temperature or normally work when the temperature of the adjusting tube is not higher than the preset temperature, thereby improving the overtemperature response speed of the circuit.
Drawings
FIG. 1 is a schematic diagram of an embodiment of a temperature protection circuit for a low dropout regulator according to the present invention;
FIG. 2 is a schematic diagram of another embodiment of a temperature protection circuit of a low dropout regulator according to the present invention;
FIG. 3 is a schematic diagram of an embodiment of a V_CTAT generation circuit of a temperature protection circuit for a low dropout regulator according to the present invention;
FIG. 4 is a schematic diagram of an embodiment of a low dropout regulator of a temperature protection circuit of a low dropout regulator according to the present invention;
fig. 5 is a schematic flow chart of an embodiment of a temperature protection method of a low dropout voltage regulator according to the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
Referring to fig. 1, a temperature protection circuit of a low dropout voltage regulator provided by an embodiment of the present invention is applied to a low dropout voltage regulator, wherein a first input terminal of the low dropout voltage regulator is connected with a first output terminal of the temperature protection circuit; the first voltage is connected to the second input end of the low-voltage-drop voltage stabilizer;
the temperature protection circuit includes: a differential input comparator, a schmitt trigger, and a level shifter;
the first sampling end of the differential input comparator is used as the first input end of the temperature protection circuit, the second sampling end of the differential input comparator is used as the second input end of the temperature protection circuit, the output end of the differential input comparator is connected with the input end of the Schmitt trigger, the output end of the Schmitt trigger is connected with the input end of the level shifter, and the output end of the level shifter is used as the first output end of the temperature protection circuit;
the temperature protection circuit is used for collecting first voltage through a first input end, collecting second voltage through a second input end and outputting a first output signal through a first output end; the first output signal is a low voltage signal or a high voltage signal; the first voltage is a reference voltage; the second voltage is inversely proportional to absolute temperature;
the low-voltage-drop voltage stabilizer is used for outputting a first output voltage through an output end of the low-voltage-drop voltage stabilizer according to a first output signal acquired by a first input end and a first voltage acquired by a second input end; if the first output signal is a low voltage signal, the low-voltage-drop voltage stabilizer stops working; and if the first output signal is a high-voltage signal, the low-voltage-drop voltage stabilizer works normally and outputs a first output voltage.
Further, the differential input comparator includes: a PMOS current source, a PMOS differential input pair, and an active current mirror load;
the PMOS differential input pair includes a first differential element and a second differential element; taking a grid electrode of a first differential element as a first sampling end of a differential input comparator; the second sampling end of the differential input comparator is connected with the grid electrode of the second differential element; the source electrode of the first differential element and the source electrode of the second differential element are connected with the drain electrode of the PMOS current source; the grid electrode of the PMOS current source is connected with bias voltage, and the source electrode of the PMOS current source is connected with a first power supply;
the active current mirror load includes a first load and a second load; the drain electrode of the first load is connected with the drain electrode of the first differential element; the drain electrode of the first load and the grid electrode of the first load are connected with the grid electrode of the second load; the drain electrode of the second load is connected with the drain electrode of the second differential element and is used as the output end of the differential input comparator; the sources of the first load and the second load are grounded.
Further, the output end of the differential input comparator is connected with the input end of the schmitt trigger through a first connection circuit, specifically:
the first connection circuit comprises a common source amplifier and a first transistor;
the common source stage amplifier includes a second transistor and a third transistor; the grid electrode of the second transistor is connected with bias voltage, and the source electrode of the second transistor is connected with a first power supply; the grid electrode of the third transistor and the drain electrode of the second load are connected with the drain electrode of the second differential element; the source electrode of the third transistor and the source electrode of the first transistor are grounded; the drain electrode of the second transistor and the drain electrode of the third transistor are connected with the drain electrode of the first transistor and the input end of the Schmitt trigger.
Further, the schmitt trigger comprises a first PMOS, a first NMOS, a second PMOS, a second NMOS, a third PMOS and a third NMOS;
the sources of the first PMOS, the second PMOS and the third PMOS are connected to a first power supply; the sources of the first NMOS, the second NMOS and the third NMOS are all grounded;
the grid electrode of the first PMOS is connected with the grid electrode of the first NMOS and is used as the input end of the Schmitt trigger; the drain electrode of the first PMOS, the drain electrode of the first NMOS, the grid electrode of the first transistor, the drain electrode of the second PMOS, the drain electrode of the second NMOS, the grid electrode of the third PMOS and the grid electrode of the third NMOS are connected; the grid electrode of the second PMOS, the grid electrode of the second NMOS, the drain electrode of the third PMOS and the drain electrode of the third NMOS are connected and serve as the output end of the Schmitt trigger.
Further, the level shifter includes: fourth PMOS, fourth NMOS, fifth PMOS, fifth NMOS, sixth PMOS, and sixth NMOS;
the sources of the fourth PMOS, the fifth PMOS and the sixth PMOS are connected to a first power supply; the sources of the fourth NMOS, the fifth NMOS and the sixth NMOS are all grounded;
the grid electrode of the fourth PMOS, the grid electrode of the fourth NMOS and the grid electrode of the sixth NMOS are connected and serve as input ends of the level shifter; the drain electrode of the fourth PMOS, the drain electrode of the fourth NMOS and the grid electrode of the fifth NMOS are connected; the drain electrode of the fifth NMOS, the drain electrode of the fifth PMOS and the grid electrode of the sixth PMOS are connected; the grid electrode of the fifth PMOS, the drain electrode of the sixth PMOS and the drain electrode of the sixth NMOS are connected and serve as output ends of the level shifter.
As a preferred embodiment, please refer to fig. 2, which is a schematic diagram of a preferred temperature protection circuit, comprising: a differential input comparator, a schmitt trigger, and a level shifter;
wherein the differential input comparator comprises differential amplifiers M1-M5; m1 and M2 are PMOS differential input pairs, M3 is a PMOS current source, and M4 and M5 are active current mirror loads.
The gates of M1 and M2 are respectively connected with V_CTAT (voltage inversely proportional to absolute temperature) and V_REF (reference voltage which is provided by band gap reference and is independent of temperature), the drain electrode of M1 is connected with the drain electrode of an active load M4, and the drain electrode of M2 is connected with the drain electrode of an active load M5.
The gate of M3 is connected with bias voltage, the source of M3 is connected with VDD, and the drain of M3 is connected with the sources of M1 and M2. M4 is diode connected, namely drain electrode and grid electrode are connected, M4 grid electrode is connected with M5 grid electrode, M4 and M5 source electrode are connected with GND, and M5 drain electrode is used as output of differential comparator.
The output of differential input comparator is connected with the input of schmitt trigger through first connecting circuit, first connecting circuit includes: transistors M6 and M7 constitute a common source amplifier and transistor M8. The grid electrode of M6 is connected with the same bias voltage as the grid electrode of M3, the source electrode of M6 is connected with VDD, the grid electrode of M7 is connected with the drain electrode of M5, the source electrode of M7 is connected with GND, the drain electrodes of M6, M7 and M8 are connected, and serve as output ends to be connected with the input end of the Schmitt trigger, and the source electrode of M8 is connected with GND.
The schmitt trigger is composed of transistors M9-M14, where M9, M11, and M13 are PMOS, and M10, M12, and M14 are NMOS. M9 and M10, M13 and M14 respectively form two pairs of inverters. The source electrode of PMOS in the inverter is connected with VDD, and the source electrode of NMOS is connected with GND; the source electrode of M11 is connected with VDD, and the source electrode of M12 is connected with GND; the gates of M9 and M10 are connected as input signals of the Schmitt trigger and are also input ends of the inverters M9-M10, and the drains of M13 and M14 are connected as output ends of the inverters M13-M14.
The input ends of the inverters M9-M10 are connected with the drains of the M7 and M8, and the drains of the M9 and M10 are connected as the output ends of the inverters M9-M10, the gates of the M8, the drains of the M11 and M12 and the output ends of the inverters M13-M14. The output ends of the inverters M13-M14 are fed back to the grids of the M11-M12, namely the output ends of the inverters M13-M14 are connected with the grids of the M11 and M12, and meanwhile, the output signals serving as Schmitt triggers are also connected with the input ends of the level shifters to control the level shifters.
The level shifter is composed of transistors M15-M20, where M15, M19, and M20 are PMOS and M16, M17, and M18 are NMOS. The gates of M15 and M16 are connected as the input terminals of inverters M15-M16, and the output terminals of the Schmitt trigger are connected with the input terminals of inverters M15-M16 and the gate of M18. The drains of M15 and M16 are connected as the output terminals of inverters M15-M16, and the outputs of inverters M15-M16 are connected with the gate of M17. The source of M17 is connected to GND, and the drain is connected to the drain of M19 and the gate of M20. The source of M18 is connected to GND, the drain of M18 is connected to the drain of M20 and the gate of M19, and the signal TEM_SHDN is output as the output terminal of the level shifter.
As a preferred embodiment, v_ctat decreases when the temperature of the tuning tube increases, and v_ref is set higher than v_ctat when the temperature is higher than a preset temperature. When V_REF is higher than V_CTAT, the differential input comparator outputs a low voltage, so that transistor M7 is turned off and the drain terminal of M7 is at a high voltage. The high voltage at the drain end of M7 is turned over to be low voltage through an inverter consisting of M9-M10, and turned over to be high voltage through an inverter consisting of M13 and M14, namely the Schmitt trigger outputs high voltage.
The transistor M8 is used to stabilize the voltage at the input terminal of the inverter, and if the input terminal of the inverter is high voltage and the output terminal is low voltage, the transistor M8 is turned off, so that the input terminal of the inverter is locked at the high voltage, and vice versa. Transistors M9-M14 constitute schmitt triggers that function to reduce the disturbance of the input noise and to flip quickly at the output.
When the Schmitt trigger outputs high voltage, M18 is conducted, and the TEM_SHDN voltage is pulled down to conduct M19; the high voltage output by the Schmitt trigger is turned over by an inverter consisting of M15-M16 to output low voltage, M17 is cut off, the drain end of M17 is high voltage, and M20 is cut off; the TEM SHDN outputs a low voltage, i.e., the temperature protection circuit outputs a low voltage.
When the temperature is lowered from an excessively high temperature, v_ctat becomes large as the temperature is lowered, and when the temperature is not higher than a preset temperature, v_ctat is set higher than v_ref. When v_ctat is higher than v_ref, the differential input comparator outputs a high voltage so that M7 is turned on, the M7 drain voltage is pulled down, and a low voltage is input to the schmitt trigger so that the schmitt trigger outputs a low voltage. The low voltage output by the Schmitt trigger is inverted through the inverters M15-M16 to output high voltage, so that M17 is turned on, M18 is turned off, M20 is turned on by pulling down the grid voltage of M20 by M17, the TEM_SHDN voltage is pulled up, and the TEM_SHDN outputs high voltage, namely the temperature protection circuit outputs high voltage.
Further, the second voltage is generated by a v_ctat generation circuit;
referring to fig. 3, the v_ctat generation circuit specifically includes: a reference current source, a resistor and a bipolar transistor;
the output end of the reference current source and one end of the resistor are connected with the drain electrode of the bipolar transistor; the other end of the resistor is connected with the grid electrode of the bipolar transistor; the source electrode of the bipolar transistor is grounded; the base-emitter voltage of the bipolar transistor is taken as a second voltage, which is inversely proportional to absolute temperature.
Further, the low dropout regulator includes: the error amplifier, the adjusting tube, the first feedback resistor, the second feedback resistor, the first pull-up device and the second pull-up device;
the source electrode of the first pull-up device is connected with a first power supply, the drain electrode of the first pull-up device is connected with the source electrode of the second pull-up device, the drain electrode of the second pull-up device is connected with the output end of the error amplifier, the grid electrode of the first pull-up device is connected with the grid electrode of the second pull-up device and is used as a first input end of the low-voltage drop-out voltage stabilizer, and the first input end is used for collecting a first output signal of a first output end of the temperature protection circuit;
the source electrode of the adjusting tube is connected with a first power supply, the drain electrode of the adjusting tube is used as the output end of the low-voltage-drop voltage stabilizer, and the drain electrode of the adjusting tube is connected with one end of a first feedback resistor; the other end of the first feedback resistor is connected with one end of a second feedback resistor, and the other end of the second feedback resistor is grounded;
and the inverting input end of the error amplifier is used as the second input end of the low-voltage-drop voltage stabilizer, the first voltage is connected into the inverting input end, the non-inverting input end of the error amplifier is connected into the feedback voltage generated by the second feedback resistor, and the output end of the error amplifier, the grid electrode of the adjusting tube and the drain electrode of the second pull-up device are connected.
Further, the low-voltage drop voltage stabilizer stops working after receiving the low-voltage signal, specifically:
when the grid electrode of the first pull-up device and the grid electrode of the second pull-up device receive low voltage signals output by the temperature protection circuit, the first pull-up device and the second pull-up device are conducted to generate pull-up current; and the pull-up current adjusts the grid voltage of the adjusting tube to be the same as the first power supply voltage, so that the adjusting tube is closed, and the low-voltage-drop voltage stabilizer stops working.
Further, the low dropout voltage regulator normally works after receiving the high voltage signal, specifically:
when the grid electrode of the first pull-up device and the grid electrode of the second pull-up device receive the high voltage signals output by the temperature protection circuit, the first pull-up device and the second pull-up device are cut off, the adjusting tube is conducted, and the low-voltage-drop voltage stabilizer works normally.
As a preferred embodiment, please refer to fig. 4, which is a schematic diagram of a preferred low dropout voltage regulator, comprising: the error amplifier, the adjusting tube MP, the first feedback resistor R1, the second feedback resistor R2, the first pull-up device M21 and the second pull-up device M22;
the inverting input end of the error amplifier EA is connected with the reference voltage, the non-inverting input end of the error amplifier EA is connected with the feedback voltage generated by the feedback resistor, and the output end of the error amplifier EA is connected with the grid electrode of the adjusting tube MP. The source electrode of the regulating tube MP is connected with VDD, the drain electrode of MP outputs voltage VOUT, and one end of R1 is connected at the same time; the other end of R1 and one end of R2 are connected with the EA non-inverting input end; the other end of R2 is connected with GND. The pull-up devices M21 and M22 are connected in series, namely, the drain electrode of M21 is connected with the source electrode of M22, the source electrode of M21 is connected with VDD, the grid electrodes of M21 and M22 are connected with THEM_SHDN, and the drain electrode of M22 is connected with the grid electrode of the regulating tube MP.
As a preferred embodiment, when the gates of M21 and M22 receive the low voltage signal of TEM_SHDN outputted by the temperature protection circuit, M21-M22 is turned on to generate a pull-up current, the gate voltage of the regulator tube MP is pulled to a voltage close to the VDD power supply, MP is turned off, and the low dropout regulator (LDO) stops working.
After the LDO stops working, the temperature protection circuit outputs high voltage. TEM_SHDN becomes high, M21-M22 is cut off, the grid voltage of the regulating tube MP is recovered to be normal, MP is conducted, and the LDO works normally.
The implementation of the embodiment of the invention has the following effects:
the temperature protection circuit is constructed by the differential input comparator, the Schmidt trigger and the level shifter which are sequentially connected, and the first voltage and the second voltage are compared by the differential input comparator to judge whether the adjusting tube is over-heated or not. And if the temperature is over, controlling the differential input comparator to output high voltage. The high voltage output by the differential input comparator passes through the Schmitt trigger to reduce the interference of input noise and quickly overturn at the output end, and the Schmitt trigger outputs the high voltage; the level shifter inverts the voltage to output low voltage after receiving the high voltage output by the Schmitt trigger; the low voltage output by the level shifter is input into the low-dropout voltage regulator to stop the operation. Compared with the existing temperature protection circuit, the temperature protection circuit provided by the invention has the advantages that the structure is simpler, the occupied chip area is small, and the judgment and response on whether the adjusting tube is over-temperature can be rapidly carried out through the voltage comparison of the differential input comparator and the voltage processing of the Schmidt trigger and the level shifter, so that the over-temperature response speed of the circuit is improved.
Example two
Referring to fig. 5, a temperature protection method of a low dropout voltage regulator according to an embodiment of the present invention includes steps S201 to S202:
step S201: judging whether the temperature of the adjusting tube is higher than a preset temperature or not through the first voltage and the second voltage acquired by the temperature protection circuit of the low-voltage drop voltage stabilizer;
step S202: if the second voltage is lower than the first voltage, determining that the temperature of the adjusting tube is higher than a preset temperature, and controlling the temperature protection circuit to output a low voltage signal so that the low voltage drop voltage stabilizer stops working after receiving the low voltage signal;
if the second voltage is not lower than the first voltage, determining that the temperature of the adjusting tube is not higher than the preset temperature, and controlling the temperature protection circuit to output a high-voltage signal so that the low-voltage-drop voltage stabilizer can work normally after receiving the low-voltage signal.
The temperature protection method of the low-voltage-drop voltage stabilizer is applied to the temperature protection circuit of the low-voltage-drop voltage stabilizer in the embodiment of the method. The options in the method embodiments described above are also applicable to this embodiment and will not be described in detail here. The rest of the embodiments of the present application may refer to the content of the method embodiments described above, and in this embodiment, no further description is given.
The implementation of the embodiment of the invention has the following effects:
the invention can rapidly judge and respond whether the temperature of the adjusting tube is higher than the preset temperature by comparing the voltage of the differential input comparator of the temperature protection circuit of the low-voltage drop voltage stabilizer and processing the voltage of the Schmidt trigger and the level shifter, and control the working state of the low-voltage drop voltage stabilizer, and stop working when the temperature of the adjusting tube is higher than the preset temperature or normally work when the temperature of the adjusting tube is not higher than the preset temperature, thereby improving the over-temperature response speed of the circuit.
Example III
Correspondingly, the invention further provides a computer readable storage medium, which comprises a stored computer program, wherein the computer program controls equipment where the computer readable storage medium is located to execute the temperature protection method of the low-voltage-drop voltage stabilizer according to any embodiment.
The computer program may be divided into one or more modules/units, which are stored in the memory and executed by the processor to accomplish the present invention, for example. The one or more modules/units may be a series of computer program instruction segments capable of performing the specified functions, which instruction segments are used for describing the execution of the computer program in the terminal device.
The terminal equipment can be computing equipment such as a desktop computer, a notebook computer, a palm computer, a cloud server and the like. The terminal device may include, but is not limited to, a processor, a memory.
The processor may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, which is a control center of the terminal device, and which connects various parts of the entire terminal device using various interfaces and lines.
The memory may be used to store the computer program and/or the module, and the processor may implement various functions of the terminal device by running or executing the computer program and/or the module stored in the memory and invoking data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function, and the like; the storage data area may store data created according to the use of the mobile terminal, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, smart Media Card (SMC), secure Digital (SD) Card, flash Card (Flash Card), at least one disk storage device, flash memory device, or other volatile solid-state storage device.
Wherein the terminal device integrated modules/units may be stored in a computer readable storage medium if implemented in the form of software functional units and sold or used as stand alone products. Based on such understanding, the present invention may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each of the method embodiments described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth.
The foregoing embodiments have been provided for the purpose of illustrating the general principles of the present invention, and are not to be construed as limiting the scope of the invention. It should be noted that any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without departing from the spirit and principles of the present invention are intended to be included in the scope of the present invention.
Claims (10)
1. The temperature protection circuit of the low-voltage-drop voltage stabilizer is characterized by being applied to the low-voltage-drop voltage stabilizer, wherein a first input end of the low-voltage-drop voltage stabilizer is connected with a first output end of the temperature protection circuit; the first voltage is connected to the second input end of the low-voltage-drop voltage stabilizer;
the temperature protection circuit includes: a differential input comparator, a schmitt trigger, and a level shifter;
the first sampling end of the differential input comparator is used as the first input end of the temperature protection circuit, the second sampling end of the differential input comparator is used as the second input end of the temperature protection circuit, the output end of the differential input comparator is connected with the input end of the Schmitt trigger, the output end of the Schmitt trigger is connected with the input end of the level shifter, and the output end of the level shifter is used as the first output end of the temperature protection circuit;
the temperature protection circuit is used for collecting first voltage through a first input end, collecting second voltage through a second input end and outputting a first output signal through a first output end; the first output signal is a low voltage signal or a high voltage signal; the first voltage is a reference voltage; the second voltage is inversely proportional to absolute temperature;
the low-voltage-drop voltage stabilizer is used for outputting a first output voltage through an output end of the low-voltage-drop voltage stabilizer according to a first output signal acquired by a first input end and a first voltage acquired by a second input end; if the first output signal is a low voltage signal, the low-voltage-drop voltage stabilizer stops working; and if the first output signal is a high-voltage signal, the low-voltage-drop voltage stabilizer works normally and outputs a first output voltage.
2. The temperature protection circuit of a low dropout regulator of claim 1, wherein said differential input comparator comprises: a PMOS current source, a PMOS differential input pair, and an active current mirror load;
the PMOS differential input pair includes a first differential element and a second differential element; taking a grid electrode of a first differential element as a first sampling end of a differential input comparator; the second sampling end of the differential input comparator is connected with the grid electrode of the second differential element; the source electrode of the first differential element and the source electrode of the second differential element are connected with the drain electrode of the PMOS current source; the grid electrode of the PMOS current source is connected with bias voltage, and the source electrode of the PMOS current source is connected with a first power supply;
the active current mirror load includes a first load and a second load; the drain electrode of the first load is connected with the drain electrode of the first differential element; the drain electrode of the first load and the grid electrode of the first load are connected with the grid electrode of the second load; the drain electrode of the second load is connected with the drain electrode of the second differential element and is used as the output end of the differential input comparator; the sources of the first load and the second load are grounded.
3. The temperature protection circuit of a low dropout regulator of claim 2, wherein the output terminal of the differential input comparator is connected to the input terminal of the schmitt trigger through a first connection circuit, specifically:
the first connection circuit comprises a common source amplifier and a first transistor;
the common source stage amplifier includes a second transistor and a third transistor; the grid electrode of the second transistor is connected with bias voltage, and the source electrode of the second transistor is connected with a first power supply; the grid electrode of the third transistor and the drain electrode of the second load are connected with the drain electrode of the second differential element; the source electrode of the third transistor and the source electrode of the first transistor are grounded; the drain electrode of the second transistor and the drain electrode of the third transistor are connected with the drain electrode of the first transistor and the input end of the Schmitt trigger.
4. The temperature protection circuit of a low dropout regulator of claim 1, wherein said schmitt trigger comprises a first PMOS, a first NMOS, a second PMOS, a second NMOS, a third PMOS, and a third NMOS;
the sources of the first PMOS, the second PMOS and the third PMOS are connected to a first power supply; the sources of the first NMOS, the second NMOS and the third NMOS are all grounded;
the grid electrode of the first PMOS is connected with the grid electrode of the first NMOS and is used as the input end of the Schmitt trigger; the drain electrode of the first PMOS, the drain electrode of the first NMOS, the grid electrode of the first transistor, the drain electrode of the second PMOS, the drain electrode of the second NMOS, the grid electrode of the third PMOS and the grid electrode of the third NMOS are connected; the grid electrode of the second PMOS, the grid electrode of the second NMOS, the drain electrode of the third PMOS and the drain electrode of the third NMOS are connected and serve as the output end of the Schmitt trigger.
5. The temperature protection circuit of a low dropout regulator of claim 1, wherein said level shifter comprises: fourth PMOS, fourth NMOS, fifth PMOS, fifth NMOS, sixth PMOS, and sixth NMOS;
the sources of the fourth PMOS, the fifth PMOS and the sixth PMOS are connected to a first power supply; the sources of the fourth NMOS, the fifth NMOS and the sixth NMOS are all grounded;
the grid electrode of the fourth PMOS, the grid electrode of the fourth NMOS and the grid electrode of the sixth NMOS are connected and serve as input ends of the level shifter; the drain electrode of the fourth PMOS, the drain electrode of the fourth NMOS and the grid electrode of the fifth NMOS are connected; the drain electrode of the fifth NMOS, the drain electrode of the fifth PMOS and the grid electrode of the sixth PMOS are connected; the grid electrode of the fifth PMOS, the drain electrode of the sixth PMOS and the drain electrode of the sixth NMOS are connected and serve as output ends of the level shifter.
6. The temperature protection circuit of a low dropout regulator of claim 1, wherein said second voltage is generated by a v_ctat generating circuit;
the V_CTAT generation circuit specifically comprises: a reference current source, a resistor and a bipolar transistor;
the output end of the reference current source and one end of the resistor are connected with the drain electrode of the bipolar transistor; the other end of the resistor is connected with the grid electrode of the bipolar transistor; the source electrode of the bipolar transistor is grounded; the base-emitter voltage of the bipolar transistor is taken as a second voltage, which is inversely proportional to absolute temperature.
7. The temperature protection circuit of a low dropout regulator of claim 1, wherein said low dropout regulator comprises: the error amplifier, the adjusting tube, the first feedback resistor, the second feedback resistor, the first pull-up device and the second pull-up device;
the source electrode of the first pull-up device is connected with a first power supply, the drain electrode of the first pull-up device is connected with the source electrode of the second pull-up device, the drain electrode of the second pull-up device is connected with the output end of the error amplifier, the grid electrode of the first pull-up device is connected with the grid electrode of the second pull-up device and is used as a first input end of the low-voltage drop-out voltage stabilizer, and the first input end is used for collecting a first output signal of a first output end of the temperature protection circuit;
the source electrode of the adjusting tube is connected with a first power supply, the drain electrode of the adjusting tube is used as the output end of the low-voltage-drop voltage stabilizer, and the drain electrode of the adjusting tube is connected with one end of a first feedback resistor; the other end of the first feedback resistor is connected with one end of a second feedback resistor, and the other end of the second feedback resistor is grounded;
and the inverting input end of the error amplifier is used as the second input end of the low-voltage-drop voltage stabilizer, the first voltage is connected into the inverting input end, the non-inverting input end of the error amplifier is connected into the feedback voltage generated by the second feedback resistor, and the output end of the error amplifier, the grid electrode of the adjusting tube and the drain electrode of the second pull-up device are connected.
8. The temperature protection circuit of a low dropout regulator of claim 7, wherein said low dropout regulator stops operating after receiving said low voltage signal, specifically:
when the grid electrode of the first pull-up device and the grid electrode of the second pull-up device receive low voltage signals output by the temperature protection circuit, the first pull-up device and the second pull-up device are conducted to generate pull-up current; and the pull-up current adjusts the grid voltage of the adjusting tube to be the same as the first power supply voltage, so that the adjusting tube is closed, and the low-voltage-drop voltage stabilizer stops working.
9. The temperature protection circuit of a low dropout regulator of claim 7, wherein said low dropout regulator operates normally after receiving said high voltage signal, specifically:
when the grid electrode of the first pull-up device and the grid electrode of the second pull-up device receive the high voltage signals output by the temperature protection circuit, the first pull-up device and the second pull-up device are cut off, the adjusting tube is conducted, and the low-voltage-drop voltage stabilizer works normally.
10. A temperature protection method for a low dropout voltage regulator, comprising:
judging whether the temperature of the adjusting tube is higher than a preset temperature or not through the first voltage and the second voltage acquired by the temperature protection circuit of the low-dropout voltage regulator according to any one of claims 1 to 9;
if the second voltage is lower than the first voltage, determining that the temperature of the adjusting tube is higher than a preset temperature, and controlling the temperature protection circuit to output a low voltage signal so that the low voltage drop voltage stabilizer stops working after receiving the low voltage signal;
if the second voltage is not lower than the first voltage, determining that the temperature of the adjusting tube is not higher than the preset temperature, and controlling the temperature protection circuit to output a high-voltage signal so that the low-voltage-drop voltage stabilizer can work normally after receiving the low-voltage signal.
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| CN202310502020.8A CN116540821A (en) | 2023-05-06 | 2023-05-06 | Temperature protection circuit and method for low-voltage-drop voltage stabilizer |
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| CN202310502020.8A CN116540821A (en) | 2023-05-06 | 2023-05-06 | Temperature protection circuit and method for low-voltage-drop voltage stabilizer |
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