CN-117193455-B - Power control circuit, chip, low dropout linear voltage regulator and equipment

CN117193455BCN 117193455 BCN117193455 BCN 117193455BCN-117193455-B

Abstract

The application provides a power control circuit, a chip, a low dropout linear regulator and equipment. The voltage detector transmits a first current to the current feedback device in a case where a voltage difference between the input voltage and the output voltage is greater than a threshold voltage. The input voltage is the input voltage received by the input end of the low-dropout linear voltage regulator, and the output voltage is the voltage provided by the output end of the low-dropout linear voltage regulator. The current feedback device controls the output current of the mirror tube to be reduced according to the first current so as to control the output current of the power tube in the low-dropout linear voltage regulator to be reduced, and the power of the power tube is smaller than or equal to the threshold power. Therefore, the linear increase of the power tube along with the increase of the voltage difference between the input voltage and the output voltage is avoided, and the damage of the power tube is prevented.

Inventors

LU FENG
WU WENHAO
Zou Rongyan

Assignees

上海南芯半导体科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20231023

Claims (10)

1. The power control circuit is characterized by being applied to a low dropout linear voltage regulator, and comprises a voltage detector and a current feedback device; The first input end of the voltage detector is electrically connected with the input end of the low dropout linear voltage regulator, the second input end of the voltage detector is electrically connected with the output end of the low dropout linear voltage regulator, the output end of the voltage detector is electrically connected with the input end of the current feedback device, the second end of the current feedback device is electrically connected with the first input end of the first amplifier in the low dropout linear voltage regulator, and the third end of the current feedback device is electrically connected between the mirror tube and the second voltage feedback module in the low dropout linear voltage regulator; the voltage detector is used for transmitting a first current to the current feedback device when detecting that the voltage difference between the input voltage and the output voltage is larger than a threshold voltage; The current feedback device is used for controlling the output current of the mirror tube to be reduced according to the first current so as to control the output current of the power tube in the low dropout linear voltage stabilizer to be reduced, so that the power of the power tube is smaller than or equal to a threshold power; the mirror tube and the power tube form a current mirror structure, and the mirror tube and the second voltage feedback module are connected in series between the input end and the ground end; The second input end of the first amplifier is used for receiving a first reference voltage, the output end of the first amplifier is electrically connected with the positive electrode of the second diode, and the negative electrode of the second diode is electrically connected with the control end of the power tube.
2. The power control circuit of claim 1, wherein the voltage detector comprises a second resistor, a third resistor, and a second transistor; the first end of the second resistor is electrically connected between the input end of the low dropout linear voltage regulator and the first end of the power tube, the second end of the second resistor is electrically connected with the first end of the second transistor, the control end of the second transistor is electrically connected with the output end of the low dropout linear voltage regulator, the second end of the second transistor is electrically connected with the first end of the third resistor, and the second end of the third resistor is grounded.
3. The power control circuit of claim 2, wherein the current feedback device comprises a first diode and a fourth resistor; the first end of the first diode is electrically connected with the third end of the voltage detector, the second end of the first diode is electrically connected with the first input end of the first amplifier, the first end of the fourth resistor is electrically connected between the second end of the first diode and the first input end of the first amplifier, and the second end of the fourth resistor is electrically connected between the mirror tube and the second voltage feedback module.
4. The power control circuit of claim 3, wherein, The calculation formula of the threshold voltage is as follows: ; Wherein, the Representing the threshold voltage, VREF2 represents a first reference voltage received at a second input of the first amplifier, Representing the voltage of the first diode, The resistance value of the second resistor is indicated, The resistance of the third resistor is shown.
5. The power control circuit of claim 4, wherein, The calculation formula of the output current of the power tube is as follows: ; the power calculation formula of the power tube is as follows: ; Wherein, the Representing the output current of the power tube, Representing the ratio of the output current of the power tube to the output current of the mirror tube, Representing the resistance value of the fourth resistor, Represents the resistance value of the second voltage feedback module, Which is indicative of the voltage at which the input voltage is to be applied, A first intermediate value is indicated and a second intermediate value is indicated, A second intermediate value is indicated and is used to represent, Which is indicative of the output voltage of the power converter, Representing the power of the power tube.
6. The power control circuit of claim 5, wherein, The calculation formula of the threshold power is as follows: Wherein, the method comprises the steps of, Representing the threshold power.
7. A method of implementing a power control circuit as claimed in any one of claims 1 to 6, the method comprising: the voltage detector transmits a first current to the current feedback device when detecting that a voltage difference between the input voltage and the output voltage is greater than a threshold voltage; And the current feedback device controls the output current of the mirror tube to be reduced according to the first current so as to control the output current of the power tube to be reduced, so that the power of the power tube is smaller than or equal to the threshold power.
8. The low-dropout linear voltage regulator is characterized by comprising an input end, an output end, a power tube, a mirror tube, a first voltage feedback module, a second voltage feedback module, a first amplifier, a second diode and the power control circuit of any one of claims 1-6; the power tube and the first voltage feedback module are connected in series between the input end and the ground end; The mirror tube and the power tube form a current mirror structure, and the mirror tube and the second voltage feedback module are connected in series between the input end and the ground end; The first input end of the first amplifier is electrically connected with the second end of the current feedback device in the power control circuit, the second input end is used for receiving a first reference voltage, the output end is electrically connected with the positive electrode of the second diode, and the negative electrode of the second diode is electrically connected with the control end of the power tube; The first input end of the second amplifier is coupled with the first voltage feedback module, the second input end is used for receiving a second reference voltage, and the output end is electrically connected with the control end of the power tube.
9. A chip comprising the power control circuit according to any one of claims 1 to 6, or the low dropout linear regulator according to claim 8.
10. An electronic device comprising the chip of claim 9.

Description

Power control circuit, chip, low dropout linear voltage regulator and equipment Technical Field The present application relates to the field of low dropout linear voltage regulators, and in particular, to a power control circuit, a chip, a low dropout linear voltage regulator, and a device. Background The low dropout linear regulator (Low Dropout Regulator, LDO) has a current limiting protection function that enables the LDO to output a constant output current if the output voltage of the LDO is below a preset threshold. In the conventional art, as shown in fig. 1, a low dropout linear regulator of an LDO includes a power transistor, and the power of the power transistor increases linearly with the voltage difference between the input voltage of the LDO and the output voltage of the LDO. Since the power of the power tube increases linearly, the temperature of the power tube increases, and the power tube is damaged. Therefore, how to design a low dropout linear regulator to avoid the linear increase of the power tube along with the increase of the voltage difference between the input voltage of the LDO and the output voltage of the LDO, and prevent the damage of the power tube, is a technical problem to be solved. Disclosure of Invention The application provides a power control circuit, a chip, a low dropout linear regulator and equipment, which are used for solving the problem that the power of a power tube is linearly increased along with the increase of the voltage difference between the input voltage of an LDO (low dropout regulator) and the output voltage of the LDO, so that the power tube is damaged. In a first aspect, the application provides a power control circuit for a low dropout linear regulator, the power control circuit comprising a voltage detector and a current feedback device. The first input end of the voltage detector is electrically connected with the input end of the low-dropout linear voltage regulator, the second input end of the voltage detector is electrically connected with the output end of the low-dropout linear voltage regulator, the output end of the voltage detector is electrically connected with the input end of the current feedback device, the second end of the current feedback device is electrically connected with the first input end of the first amplifier in the low-dropout linear voltage regulator, and the third end of the current feedback device is electrically connected between the mirror tube and the second voltage feedback module in the low-dropout linear voltage regulator. The input end of the low-dropout linear voltage regulator is used for receiving the input voltage, and the output end of the low-dropout linear voltage regulator is used for providing the output voltage. And a voltage detector for transmitting the first current to the current feedback device in case that it is detected that the voltage difference between the input voltage and the output voltage is greater than the threshold voltage. And the current feedback device is used for controlling the output current of the mirror tube to be reduced according to the first current so as to control the output current of the power tube in the low-dropout linear voltage regulator to be reduced, so that the power of the power tube is smaller than or equal to the threshold power. Through the power control circuit provided by the first aspect, the voltage detector transmits the first current to the current feedback device under the condition that the voltage difference between the input voltage and the output voltage is larger than the voltage threshold value, and the current feedback device controls the output current of the mirror tube to be reduced according to the first current so as to control the output current of the power tube to be reduced, so that the power of the power tube is smaller than or equal to the threshold power, namely, the power of the power tube is smaller than or equal to the threshold power under the condition that the voltage difference between the input voltage and the output voltage is increased, the power of the power tube is prevented from being linearly increased along with the increase of the voltage difference between the input voltage and the output voltage, the temperature rise of the power tube is further prevented, and the damage of the power tube is prevented. In one possible design, the voltage detector includes a second resistor, a third resistor, and a second transistor. The first end of the second resistor is electrically connected between the input end of the low dropout linear voltage regulator and the first end of the power tube, the second end of the second resistor is electrically connected with the first end of the second transistor, the control end of the second transistor is electrically connected with the output end of the low dropout linear voltage regulator, the second end of the second transistor is electrically connected with the first end of the third resistor,