CN-121979348-A - Low-dropout linear voltage stabilizing circuit and chip

CN121979348ACN 121979348 ACN121979348 ACN 121979348ACN-121979348-A

Abstract

The application discloses a low-dropout linear voltage stabilizing circuit and a chip, which comprise a voltage input end, a voltage output end, a power tube, a detection transistor, a feedback control circuit, a rate regulation circuit and a current limiting circuit, wherein the first end of the power tube is connected with the voltage input end, the second end of the power tube is connected with the voltage output end, the first end of the detection transistor is connected with the voltage input end, the control end of the detection transistor is connected with the control end of the power tube, the feedback control circuit is used for generating corresponding regulation signals based on an accessed first reference voltage and a current target voltage and outputting the corresponding regulation signals to the control end of the power tube and the control end of the detection transistor, the rate regulation circuit is used for controlling the current change rate when the feedback control circuit controls the output current of the power tube, and the current limiting circuit is used for limiting the output current of the power tube not to exceed a preset current threshold value. Any drop point of the low dropout linear voltage stabilizing circuit when the input voltage drops in the starting stage is limited above the reset voltage, so that the problem of chip reset caused by the drop of the input voltage in the starting stage can be avoided.

Inventors

WANG YUAN
LIU GUIYUN
Bian Yiyi

Assignees

辉芒微电子(深圳)股份有限公司

Dates

Publication Date: 20260505
Application Date: 20251229

Claims (10)

1. A low dropout linear voltage regulator circuit, characterized in that it is applied to a chip, said low dropout linear voltage regulator circuit comprising: The voltage input end is used for accessing input voltage; The voltage output end is used for outputting a target voltage after the input voltage is regulated; the first end of the power tube is connected with the voltage input end, and the second end of the power tube is connected with the voltage output end; the first end of the detection transistor is connected with the voltage input end, and the control end of the detection transistor is connected with the control end of the power tube; The feedback control circuit comprises a first voltage input end, a second voltage input end and a control end, wherein the first voltage input end is used for accessing a first reference voltage, the second voltage input end is used for accessing a current target voltage, the control end of the feedback control circuit is connected with the control end of the power tube and the control end of the detection transistor, and the feedback control circuit is used for generating corresponding regulation and control signals based on the accessed first reference voltage and the current target voltage and outputting the regulation and control signals to the control end of the power tube and the control end of the detection transistor so as to enable the power tube and the detection transistor to generate proportional current; The rate regulation circuit is connected with the control end of the feedback control circuit and is used for controlling the feedback control circuit to control the current change rate when the power tube outputs current, so that the lowest dropping point of the input voltage drop caused by the feedback control circuit in the starting stage is larger than a first preset voltage threshold value, and the first preset voltage threshold value is larger than the reset voltage of the chip; the current limiting circuit is connected with the control end of the power tube and the second end of the detection transistor and is used for limiting the output current of the power tube not to exceed a preset current threshold value and enabling the lowest dropping point of the input voltage drop caused by the output current in the starting stage to be larger than a second preset voltage threshold value, and the second voltage preset voltage threshold value is larger than the reset voltage; And when the input voltage is smaller than or equal to the reset voltage of the chip in the starting stage, resetting the chip.
2. The low dropout linear voltage regulator circuit according to claim 1, wherein said drop in input voltage during said start-up phase includes a first phase drop which is a drop in said input voltage caused by said feedback control circuit during said start-up phase and a second phase drop which is a drop in said input voltage caused by said output current during said start-up phase; The falling time period of the input voltage in the first stage and the falling time period of the input voltage in the second stage are the total time period of the input voltage falling in the starting stage.
3. The low dropout linear voltage regulator circuit according to claim 1, wherein said feedback control unit includes: The voltage dividing network is connected between the voltage output end and the ground and is used for outputting a first feedback voltage proportional to the current target voltage according to the regulated voltage; The non-inverting input end of the first error amplifier is the second voltage input end, the inverting input end of the first error amplifier is the first voltage input end, the control end of the first error amplifier is the control end of the feedback control circuit, and the first error amplifier is used for generating the regulation and control signal according to the voltage difference between the first reference voltage and the first feedback voltage.
4. A low dropout linear voltage regulator circuit according to claim 3, wherein the driving capability of the first error amplifier is adjusted to a preset driving capability such that a drop-out nadir of the input voltage caused by the feedback control circuit during the start-up phase is greater than a first preset voltage threshold.
5. The low dropout linear voltage regulator circuit according to any one of claims 1 to 4, wherein the rate adjusting circuit comprises a first capacitor, one end of the first capacitor is connected to a control end of the feedback control unit, the other end of the first capacitor is grounded, and a capacitance value of the first capacitor characterizes a current change rate when the feedback control circuit controls the output current of the power tube.
6. The low dropout linear voltage regulator circuit according to any one of claims 1 to 4, wherein said current limiting circuit comprises: The sampling resistor is connected with the second end of the detection transistor, the other end of the sampling resistor is grounded, the sampling resistor is used for adjusting the preset current threshold, the resistance of the sampling resistor represents the preset current threshold for limiting the power tube, and a connection node of the sampling resistor and the second end of the detection transistor is configured as a feedback end and is used for outputting a second feedback voltage; The comparison control circuit comprises a first input end, a second input end and a control end, wherein the first input end is used for being connected with a second reference voltage, the second input end is connected with the feedback end and used for being connected with the feedback voltage, the control end of the comparison control circuit is connected with the control end of the power tube, the comparison control circuit is used for generating a control signal based on the voltage difference between the second reference voltage and the feedback voltage and outputting the control signal to the control end of the power tube, and the control signal is used for adjusting the current flowing through the power tube.
7. The low dropout linear regulator circuit according to claim 6, wherein said comparison control circuit includes: The first end of the driving transistor is connected with the voltage input end, and the second end of the driving transistor is connected with the control end of the power tube; the non-inverting input end of the second error amplifier is used for accessing a second reference voltage, the inverting input end of the second error amplifier is connected with the feedback end, the control end of the second error amplifier is connected with the control end of the driving transistor, and the second error amplifier is used for generating the control signal based on the voltage difference between the second reference voltage and the second feedback voltage.
8. A low dropout linear voltage regulator circuit, characterized in that it is applied to a chip, said low dropout linear voltage regulator circuit comprising: The voltage input end is used for accessing input voltage; The voltage output end is used for outputting a target voltage after the input voltage is regulated; the first end of the power tube is connected with the voltage input end, and the second end of the power tube is connected with the voltage output end; The first end of the detection transistor is connected with the voltage input end, and the control end of the detection transistor is connected with the control end of the power tube; The feedback control circuit comprises a first voltage input end, a second voltage input end and a control end, wherein the first voltage input end is used for being connected with a first reference voltage, the second voltage input end is used for being connected with the target voltage, the control end of the feedback control circuit is connected with the control end of the power tube and the control end of the detection transistor, and the feedback control circuit is used for generating corresponding regulation signals based on the connected first reference voltage and the target voltage and outputting the corresponding regulation signals to the control end of the power tube and the control end of the detection transistor so as to enable the power tube and the detection transistor to generate proportional current; The current limiting and falling suppression circuit is connected with the control end of the power tube and is used for limiting the output current of the power tube to be not more than a preset current threshold value and limiting any falling point of the input voltage falling in the starting stage to be above the reset voltage of the chip; And when the input voltage is smaller than or equal to the reset voltage of the chip in the starting stage, resetting the chip.
9. The low dropout linear voltage regulator circuit according to claim 8, wherein said current limiting and droop suppression circuit comprises: The rate regulation circuit is connected with the control end of the feedback control circuit and is used for controlling the feedback control circuit to control the current change rate when the power tube outputs current, so that the lowest dropping point of the input voltage drop caused by the feedback control circuit in the starting stage is larger than a first preset voltage threshold value, and the first preset voltage threshold value is larger than the reset voltage of the chip; the current limiting circuit is connected with the control end of the power tube and the second end of the detection transistor and is used for limiting the output current of the power tube not to exceed a preset current threshold value and enabling the lowest dropping point of the input voltage drop caused by the output current in the starting stage to be larger than a second preset voltage threshold value, and the second voltage preset voltage threshold value is larger than the reset voltage; The step of dropping the input voltage in the starting stage comprises a first step of dropping the input voltage caused by the feedback control circuit in the starting stage and a second step of dropping the input voltage caused by the output current in the starting stage; The falling time period of the input voltage in the first stage and the falling time period of the input voltage in the second stage are the total time period of the input voltage falling in the starting stage.
10. A chip comprising the low dropout linear regulator circuit according to any one of claims 1 to 7 or the low dropout linear regulator circuit according to any one of claims 8 to 9.

Description

Low-dropout linear voltage stabilizing circuit and chip Technical Field The invention relates to the technical field of MCU (micro control Unit), in particular to a low dropout linear voltage stabilizing circuit and a chip. Background The low dropout linear regulator (LDO, low Dropout Regulator) is capable of converting a relatively high, wide range of input voltages to stable, accurate low voltages, thereby powering a chip that requires stable, accurate low voltages. In the related art, the low dropout linear voltage stabilizing circuit is composed of an amplifier, a feedback network and an adjusting tube, as shown in fig. 1, when the low dropout linear voltage stabilizing circuit is applied, due to charge conservation, the input voltage can drop greatly in the starting stage, and the lowest drop point in the dropping process can be smaller than or equal to the reset voltage of the chip to reset the chip, so that the low dropout linear voltage stabilizing circuit is not suitable for the chip. Disclosure of Invention The invention mainly solves the technical problems that the low-dropout linear voltage stabilizing circuit in the related art resets the chip when the lowest drop point of the input voltage in the dropping process of the starting stage is possibly smaller than or equal to the reset voltage of the chip, and is not suitable for the chip. According to a first aspect, in one embodiment of the present application, there is provided a low dropout linear voltage regulator circuit, applied to a chip, the low dropout linear voltage regulator circuit including: The voltage input end is used for accessing input voltage; The voltage output end is used for outputting a target voltage after the input voltage is regulated; the first end of the power tube is connected with the voltage input end, and the second end of the power tube is connected with the voltage output end; the first end of the detection transistor is connected with the voltage input end, and the control end of the detection transistor is connected with the control end of the power tube; The feedback control circuit comprises a first voltage input end, a second voltage input end and a control end, wherein the first voltage input end is used for accessing a first reference voltage, the second voltage input end is used for accessing a current target voltage, the control end of the feedback control circuit is connected with the control end of the power tube and the control end of the detection transistor, and the feedback control circuit is used for generating corresponding regulation and control signals based on the accessed first reference voltage and the current target voltage and outputting the regulation and control signals to the control end of the power tube and the control end of the detection transistor so as to enable the power tube and the detection transistor to generate proportional current; The rate regulation circuit is connected with the control end of the feedback control circuit and is used for controlling the feedback control circuit to control the current change rate when the power tube outputs current, so that the lowest dropping point of the input voltage drop caused by the feedback control circuit in the starting stage is larger than a first preset voltage threshold value, and the first preset voltage threshold value is larger than the reset voltage of the chip; the current limiting circuit is connected with the control end of the power tube and the second end of the detection transistor and is used for limiting the output current of the power tube not to exceed a preset current threshold value and enabling the lowest dropping point of the input voltage drop caused by the output current in the starting stage to be larger than a second preset voltage threshold value, and the second voltage preset voltage threshold value is larger than the reset voltage; And when the input voltage is smaller than or equal to the reset voltage of the chip in the starting stage, resetting the chip. In one embodiment, the step of dropping the input voltage during the start-up phase includes a first step-down, which is a step-down of the input voltage caused by the feedback control circuit during the start-up phase, and a second step-down, which is a step-down of the input voltage caused by the output current during the start-up phase; The falling time period of the input voltage in the first stage and the falling time period of the input voltage in the second stage are the total time period of the input voltage falling in the starting stage. In one embodiment, the feedback control unit includes: The voltage dividing network is connected between the voltage output end and the ground and is used for outputting a first feedback voltage proportional to the current target voltage according to the regulated voltage; The non-inverting input end of the first error amplifier is the second voltage input end, the inverting input end of the first error ampli