EP-4738672-A1 - POWER SUPPLY AND OPERATING METHOD THEREOF

EP4738672A1EP 4738672 A1EP4738672 A1EP 4738672A1EP-4738672-A1

Abstract

A power supply includes a power converter, a feedback circuit, a control signal generating circuit and a compensating circuit. The power converter generates an output voltage at an output node. The feedback circuit generates a feedback signal according to an output node voltage. The control signal generating circuit provides a control signal to the power converter according to the feedback signal. The compensating circuit includes a reference voltage circuit, a voltage dividing circuit and a switching circuit. When the output node voltage is decreased from the first voltage level to a level threshold or decreased from the first voltage level by an amplitude threshold, the switching circuit is conducted to couple the feedback circuit to the voltage dividing circuit, so the feedback circuit sets the control signal generating circuit to increase a duty cycle of the control signal and/or decrease a frequency of the control signal.

Inventors

CHOU, MING-WEI
CHEN, Sheng-jian
HSU, CHIA-CHANG

Assignees

Delta Electronics, Inc.

Dates

Publication Date: 20260506
Application Date: 20250121

Claims (15)

A power supply (100), configured to be coupled to an output node (ND1) to supply power to a load (LD1), and characterized by comprising: a power converter (130), configured to generate an output voltage (Vout) at the output node according to an input voltage (Vin); a feedback circuit (115), coupled to the output node and configured to correspondingly generate a feedback signal (FB) according to an output node voltage (VND1) of the output node; a control signal generating circuit (117), coupled to the power converter, and configured to correspondingly provide a control signal (Vctrl) to the power converter according to the feedback signal to generate the output voltage; and a compensating circuit (120), coupled between the output node and the feedback circuit, and comprising: a reference voltage circuit (REF1), coupled to the output node, and configured to correspondingly generate a reference voltage (Vref) according to the output node voltage; a voltage dividing circuit (DIV1), coupled to the reference voltage circuit, and configured to correspondingly generate a divided voltage (Vdiv) according to the reference voltage; and a switching circuit (SWC1), coupled to the voltage dividing circuit and the feedback circuit, wherein when the output node voltage increases from a preset voltage level (Vpre1) to a first voltage level (Vlev1) and then decreases from the first voltage level to a level threshold (LEV_TH) or decreases from the first voltage level by an amplitude threshold (AM_T1), the switching circuit is conducted to couple the feedback circuit to the voltage dividing circuit, so that the feedback circuit sets the control signal generating circuit to correspondingly increase a duty cycle of the control signal and/or decrease a frequency of the control signal.
The power supply of claim 1, wherein when the output node voltage decreases, the feedback circuit generates the feedback signal to correspondingly increase the duty cycle of the control signal and/or decrease the frequency of the control signal, so that the control signal generation circuit sets the power converter to increase the output voltage.
The power supply of claim 2, wherein when the output node voltage increases, the feedback circuit generates the feedback signal to correspondingly decrease the duty cycle of the control signal and/or increase the frequency of the control signal, so that the control signal generation circuit sets the power converter to decrease the output voltage.
The power supply of claim 1 or 3, wherein the feedback circuit comprises a light-emitting diode (LED1), and the light-emitting diode is configured to correspondingly generate the feedback signal according to a current flowing through the light-emitting diode.
The power supply of claim 1 or 4, wherein the voltage divider circuit comprises: a first resistor (RD1), coupled to the reference voltage circuit and the switching circuit; and a second resistor (RD2), arranged between the switching circuit, the first resistor and a ground terminal (GND), wherein when the switching circuit is conducted, the switching circuit couples the second resistor to the feedback circuit to change the current flowing through the light-emitting diode.
The power supply of claim 4 or 5, wherein when the switching circuit is conducted, the current flowing through the light-emitting diode is increased, and the control signal generating circuit increases the output voltage of the power converter according to the feedback signal.
The power supply of claim 1, wherein the reference voltage circuit comprises: a diode (D1), comprising a first terminal coupled to the output node and a second terminal coupled to the voltage dividing circuit; and a first capacitor (CD1), comprising a first terminal coupled to the output node, and a second terminal coupled to the second terminal of the diode.
The power supply of claim 1, wherein the switching circuit comprises a transistor (BJT1), a first terminal of the transistor is coupled to the voltage dividing circuit, a second terminal of the transistor is coupled to the feedback circuit, and a control terminal of the transistor is coupled to a ground terminal (GND).
An operating method of a power supply (100), wherein the power supply is coupled to an output node (ND1) to supply power to a load (LD1), the power supply comprises a power converter (130) coupled to the output node, a feedback circuit (115) coupled to the output node, a control signal generating circuit (117) coupled to the power converter, and a compensating circuit (120) coupled to the output node and the feedback circuit, the compensating circuit comprises a reference voltage circuit (REF1) coupled to the output node, a voltage dividing circuit (DIV1) coupled to the reference voltage circuit, and a switching circuit (SW1) coupled to the voltage dividing circuit and the feedback circuit, and the operating method is characterized by comprising: by setting the power converter, generating an output voltage (Vout) at the output node according to an input voltage (Vin); by setting the feedback circuit, correspondingly generating a feedback signal (FB) according to an output node voltage (VND1) of the output node; by setting the control signal generating circuit, correspondingly providing a control signal (Vctrl) to the power converter according to the feedback signal, to generate the output voltage; by setting the reference voltage circuit, correspondingly generating a reference voltage (Vref) according to the output node voltage; and by setting the voltage dividing circuit, correspondingly generating a divided voltage (Vdiv) according to the reference voltage, wherein when the output node voltage is increased from a preset voltage level (Vpre1) to a first voltage level (Vlev1) and is then decreased from the first voltage level to a level threshold (LEV_TH) or decreased from the first voltage level by an amplitude threshold (AM_T1), the switching circuit is conducted to couple the feedback circuit to the voltage dividing circuit, so that the feedback circuit sets the control signal generating circuit to correspondingly increase a duty cycle of the control signal and/or decrease a frequency of the control signal.
The operating method of claim 9, further comprising: when the output node voltage is decreased, by the feedback circuit, generating the feedback signal to correspondingly increase the duty cycle of the control signal and/or decrease the frequency of the control signal, so that the control signal generation circuit sets the power converter to increase the output voltage.
The operating method of claim 10, further comprising: when the output node voltage is increased, by the feedback circuit, generating the feedback signal to correspondingly decrease the duty cycle of the control signal and/or increase the frequency of the control signal, so that the control signal generation circuit sets the power converter to decrease the output voltage.
The operating method of claim 9 or 11, wherein the feedback circuit comprises a light-emitting diode (LED1), and the operating method further comprises: correspondingly generating the feedback signal according to a current flowing through the light-emitting diode.
The operating method of claim 9 or 12, wherein the voltage divider circuit comprises a first resistor (RD1) and a second resistor (RD2), the first resistor is coupled to the reference voltage circuit and the switching circuit, the second resistor is arranged between the switching circuit, the first resistor and a ground terminal (GND), and the operating method further comprises: when the switching circuit is conducted, by the switching circuit, coupling the second resistor to the feedback circuit to change the current flowing through the light-emitting diode.
The operating method of claim 12 or 13, further comprising: when the switching circuit is conducted, increasing the current flowing through the light-emitting diode, and increasing, by the control signal generating circuit, the output voltage of the power converter according to the feedback signal.
The operating method of claim 9, wherein the reference voltage circuit comprises a diode (D1) and a first capacitor (CD1), the diode comprises a first terminal coupled to the output node and a second terminal coupled to the voltage dividing circuit, the first capacitor comprises a first terminal coupled to the output node and a second terminal coupled to the second terminal of the diode, and the operating method further comprises: setting a limit voltage value across the first terminal and the second terminal of the diode, to generate the reference voltage at the second terminal of the diode, wherein the limit voltage value is set through a breakdown voltage of the diode and is greater than or equal to the preset voltage level.

Description

BACKGROUND Field of Invention This disclosure relates to a power supply, and in particular to a power supply that can quickly compensate for output node voltage changes. Description of Related Art A power supply can be configured to convert voltage and provide stable voltage to a load. However, when the load of the power supply is a device such as a motor, or when multiple power supplies are connected in parallel, the output of the power supply may be higher than a preset output voltage due to reasons such as back electromotive force generated by the motor or abnormal operation of one of the multiple power supplies. For example: the default output voltage value of the power supply is 24V, but due to the abnormal operation of other power supplies connected in parallel, the voltage value of the output terminal of the power supply becomes 30V. For ease of explanation, the situation in which the voltage at the output terminal of the power supply is pulled up due to external factors is referred to as "voltage external sinking". When the voltage external sinking phenomenon occurs in a well-known power supply, the voltage value at the output terminal may be increased significantly, and causing the power supply to reduce power supplying or suspend power supplying. When the voltage external sinking phenomenon disappears, it will take a certain reaction time for the power supply to return to the normal power supply state from reducing the power supplying or suspending the power supplying. As a result, the voltage at the output terminal may drop significantly, or even drop below the load-tolerable specifications, and causing malfunction or damage to the load. SUMMARY How to solve the technical problems mentioned above which caused by voltage external sinking to the power supply is an important issue that needs to be solved in this art. The present disclosure provides a power supply is coupled to an output node to supply power to a load. The power supply includes a power converter, a feedback circuit, a control signal generating circuit, and a compensating circuit. The power converter is configured to generate an output voltage at the output node according to an input voltage. The feedback circuit is coupled to the output node and configured to correspondingly generate a feedback signal according to an output node voltage of the output node. The control signal generating circuit is coupled to the power converter, and configured to correspondingly provide a control signal to the power converter according to the feedback signal, to generate the output voltage. The compensating circuit is coupled between the output node and the feedback circuit. The compensating circuit include a reference voltage circuit, a voltage dividing circuit, and a switching circuit. The reference voltage circuit is coupled to the output node, and configured to correspondingly generate a reference voltage according to the output node voltage. The voltage dividing circuit is coupled to the reference voltage circuit, and configured to correspondingly generate a divided voltage according to the reference voltage. The switching circuit, coupled to the voltage dividing circuit and the feedback circuit. When the output node voltage is increased from a preset voltage level to a first voltage level and is then decreased from the first voltage level to a level threshold or decreased from the first voltage level by an amplitude threshold, the switching circuit is conducted to couple the feedback circuit to the voltage dividing circuit, so that the feedback circuit sets the control signal generating circuit to correspondingly increase a duty cycle of the control signal and/or decrease a frequency of the control signal. The present disclosure provides an operating method of a power supply. The power supply is coupled to an output node to supply power to a load, the power supply includes a power converter coupled to the output node, a feedback circuit coupled to the output node, a control signal generating circuit coupled to the power converter, and a compensating circuit coupled to the output node and the feedback circuit. The compensating circuit includes a reference voltage circuit coupled to the output node, a voltage dividing circuit coupled to the reference voltage circuit, and a switching circuit coupled to the voltage dividing circuit and the feedback circuit. The operating method includes: by setting the power converter, generating an output voltage at the output node according to an input voltage; by setting the feedback circuit, correspondingly generating a feedback signal according to an output node voltage of the output node; by setting the control signal generating circuit, correspondingly providing a control signal to the power converter according to the feedback signal, to generate the output voltage; by setting the reference voltage circuit, correspondingly generating a reference voltage according to the output node voltage; and by setting the