CN-224233560-U - Switching power supply and primary side control circuit thereof

CN224233560UCN 224233560 UCN224233560 UCN 224233560UCN-224233560-U

Abstract

The switching power supply comprises an optical coupler and a charging protocol interaction circuit, wherein the optical coupler is coupled with the charging protocol interaction circuit, an output signal of the charging protocol interaction circuit is transmitted to the primary side control circuit through the optical coupler, the primary side control circuit comprises a signal detection unit, a counting unit, a control unit and an output parameter adjusting unit, the signal detection unit is used for comparing a feedback signal with a first reference signal and outputting a comparison signal, the counting unit is used for counting the number of pulses of the comparison signal and outputting a count value representing a target charging mode, the control unit is used for outputting a control signal according to the received count value, the output parameter adjusting unit is used for receiving the control signal and adjusting an output parameter corresponding to the target charging mode according to the control signal, and the drive control circuit is used for outputting a drive signal corresponding to the output parameter. The switching power supply and the primary side control circuit thereof provided by the utility model have the advantages that an output voltage detection circuit is not required to be additionally arranged, the packaging structure of the existing primary side control circuit can be compatible, and the cost is reduced.

Inventors

XU XIAOZHAO
GUO KAI
WANG ZHONG
GAO YANG
LIAN XINPING

Assignees

杭州士兰微电子股份有限公司

Dates

Publication Date: 20260512
Application Date: 20250526

Claims (20)

1. A primary side control circuit for a switching power supply, comprising: The signal detection unit receives a feedback signal and a first reference signal, compares the feedback signal with the first reference signal and outputs a comparison signal; The counting unit is coupled with the output end of the signal detection unit, receives the comparison signal, counts the pulse number of the comparison signal and outputs a count value, and the count value represents a target charging mode; the control unit is connected with the output end of the counting unit and outputs a control signal according to the received count value; An output parameter adjusting unit for receiving the control signal and adjusting an output parameter corresponding to a target charging mode according to the control signal; And the driving control circuit receives the output parameters and outputs driving signals corresponding to the output parameters to the switching tube.
2. The primary-side control circuit of claim 1, wherein the count value is a first type value that characterizes the target charging mode as a normal charging mode, wherein the count value is a third type value that characterizes the target charging mode as being restored to the normal charging mode, wherein the count value is a second type value that characterizes the target charging mode as being a fast charging mode, and wherein the first type value, the second type value, and the third type value are different and positive integers.
3. The primary side control circuit of claim 2, wherein the output parameter adjustment unit is adapted to adjust at least one of a second reference value corresponding to loop gain, a third reference value corresponding to output power, and a fourth reference value corresponding to overvoltage protection.
4. A primary side control circuit as claimed in claim 3, wherein the fast charge mode is of N types, N being a positive integer and N being ≡2.
5. The primary side control circuit of claim 1, wherein the signal detection unit comprises a first comparator having a first input receiving the feedback signal and a second input receiving the first reference signal, the output of the first comparator being coupled to the counting unit.
6. The primary side control circuit of claim 1, wherein the output parameter adjustment unit comprises a loop gain adjustment unit, wherein the loop gain adjustment unit is responsive to K first control signals of the control signals and adjusts a second reference value corresponding to the loop gain according to the K first control signals.
7. The primary side control circuit of claim 6, wherein the loop gain adjustment unit comprises K switch units, a resistor string formed by connecting L resistors in series and a second comparator, wherein a first end of the resistor string is connected with an internal voltage source through a pull-up resistor, and a second end of the resistor string is grounded; a first input end of the second comparator receives a sampling signal, a second input end of the second comparator is connected with a node between any two series resistors in the resistor string so as to receive the second reference value, the second comparator compares the sampling signal with the second reference value, an output end of the second comparator is connected with the driving control circuit, The ith switch unit of the K switch units is connected with two ends of the jth resistor in the resistor string in parallel, the control end of the ith switch unit receives a corresponding first control signal provided by the control unit, when the first control signal corresponding to the ith switch unit is effective, the ith switch unit is conducted and short-circuited with the jth resistor, different switch units of the K switch units are connected with two ends of different resistors in the resistor string in parallel, so that the second reference value is adjusted, The driving control circuit drives the switching tube; Wherein K, L, i is a positive integer, i is not less than 1 and not more than K, j is not less than 1 and not more than L, and L is not less than K.
8. The primary side control circuit of claim 1, wherein the output parameter adjustment unit comprises an output power adjustment unit, and wherein the output power adjustment unit is responsive to M second control signals of the control signals and adjusts a third reference value corresponding to the output power according to the M second control signals.
9. The primary side control circuit of claim 8, wherein the output power adjustment unit comprises M switching units and a third comparator, wherein: The first input end of the third comparator receives a sampling signal, the second input end of the third comparator receives a third reference signal, the output end of the third comparator is connected with the drive control circuit, The first end of each of the M switch units receives corresponding second control signals from the control unit respectively, the second end of each of the M switch units is connected with the second input end of the third comparator, the third end of each of the M switch units receives M third reference values respectively, the M switch units receive M second control signals respectively for control, when the corresponding switch unit is conducted, the corresponding third reference value is used as the third reference signal of the third comparator, and M is a positive integer.
10. The primary side control circuit of claim 1, wherein the output parameter adjustment unit comprises an overvoltage protection threshold adjustment unit, wherein the overvoltage protection threshold adjustment unit is responsive to N third control signals in the control signals and outputs a fourth reference value corresponding to overvoltage protection according to the N third control signals.
11. The primary side control circuit of claim 10, wherein the overvoltage protection threshold adjustment unit comprises N switch units and a fourth comparator, wherein: The first input end of the fourth comparator receives the power supply voltage, the second input end of the fourth comparator receives the fourth reference signal, the output end of the fourth comparator is connected with the drive control circuit, The first end of each of the N switch units receives corresponding third control signals from the control unit respectively, the second end of each of the N switch units is connected with the second input end of the fourth comparator, the third end of each of the N switch units receives N fourth reference values respectively, the N switch units receive N third control signals respectively for control, when the corresponding switch unit is conducted, the corresponding fourth reference value is used as a fourth reference signal of the fourth comparator, and N is a positive integer.
12. The primary side control circuit of claim 2, further comprising a zero clearing unit coupled to the counting unit, the zero clearing unit outputting a zero clearing signal to the counting unit when the count value is the third type value.
13. The primary side control circuit of claim 1, wherein the drive signal output by the drive control circuit controls the switching tube to be turned on or off.
14. The primary side control circuit of claim 13, wherein the signal detection unit, the counting unit, the control unit, the output parameter adjustment unit, and the drive control circuit are integrated in a same primary side control chip.
15. The primary side control circuit of claim 14, wherein the primary side control chip and the switching tube are packaged together.
16. The primary side control circuit of claim 13, wherein the signal detection unit, the counting unit, the control unit, the output parameter adjustment unit, the drive control circuit, and the switching tube are integrated in a same chip.
17. The primary side control circuit of claim 13, wherein the package structure of the primary side control circuit comprises a current sampling pin, a ground pin, a power supply pin, an output feedback pin, and a third terminal pin of the switching tube, wherein a first terminal of the switching tube is connected to the drive control circuit, a second terminal of the switching tube is connected to the sampling pin, and a third terminal of the switching tube is connected to the third terminal pin of the switching tube.
18. The primary side control circuit of claim 13, wherein a current sampling pin, a ground pin, a power supply pin, and an output feedback pin are on a first side of a package structure of the primary side control circuit, and a third terminal pin of the switching tube is on a second side of the package structure of the primary side control circuit, the first side and the second side being parallel.
19. A switching power supply is characterized by comprising an optocoupler, a charging protocol interaction circuit and a primary side control circuit, wherein the optocoupler is coupled with the charging protocol interaction circuit, a feedback signal output by the charging protocol interaction circuit is transmitted to the primary side control circuit through the optocoupler, The primary side control circuit comprises: The signal detection unit receives the feedback signal and the first reference signal, compares the feedback signal with the first reference signal and outputs a comparison signal; The counting unit is coupled with the output end of the signal detection unit, receives the comparison signal, counts the pulse number of the comparison signal and outputs a count value, and the count value represents a target charging mode; the control unit is connected with the output end of the counting unit and outputs a control signal according to the received count value; An output parameter adjusting unit for receiving the control signal and adjusting an output parameter corresponding to a target charging mode according to the control signal; And the driving control circuit receives the output parameters and outputs driving signals corresponding to the output parameters to the switching tube.
20. The switching power supply of claim 19 wherein said count value is a first type of value, said count value is indicative of said target charging mode being a normal charging mode, said count value is a third type of value, said count value is indicative of said target charging mode being restored to said normal charging mode, said number of pulses is a second type of value, said count value is indicative of said target charging mode being a fast charging mode, said first type of value, said second type of value, said third type of value being different and a positive integer.

Description

Switching power supply and primary side control circuit thereof Technical Field The utility model relates to the technical field of switching power supplies, in particular to a switching power supply and a primary side control circuit thereof. Background The rapid charging technology is widely applied to intelligent electronic equipment (such as mobile phones). Switching power supplies supporting the fast charging technology are receiving increasing attention. Conventional switching power supplies supporting fast charging require that the switching power supply have different voltage output capabilities and be capable of adjusting the output voltage to a target output voltage based on a fast charging protocol supported by the intelligent electronic device being charged. The traditional switching power supply also has the defects of 1) fixed overvoltage protection (Over Voltage Protection, OVP) threshold, which is usually set based on maximum output voltage, 2) poor power span adaptability, high limit power protection point, easiness in triggering down-conversion or hiccup (Burst) mode to cause low charging efficiency in a low-power consumption charging scene, 3) poor loop stability and lack of output voltage real-time detection and loop gain dynamic adjustment capability. Currently, there are some switching power supplies supporting fast charging, which can improve the above-mentioned shortcomings of the conventional switching power supplies. In a typical scheme, an output voltage detection circuit is additionally arranged in a primary side control circuit, and the output voltage/charging power requirement of a secondary side is analyzed in real time to carry out self-adaptive adjustment. However, in the existing switching power supply, an output voltage detection pin needs to be newly added in the primary side control chip. Disclosure of utility model The utility model aims at providing a switching power supply and a primary side control circuit thereof, and the output parameters of the primary side control circuit are adjusted through feedback signals. The utility model provides a primary side control circuit of a switching power supply, which comprises a signal detection unit, a counting unit, a control unit, an output parameter adjustment unit and a drive control circuit, wherein the signal detection unit is used for receiving a feedback signal and a first reference signal, comparing the feedback signal with the first reference signal and outputting a comparison signal, the counting unit is coupled with the output end of the signal detection unit and is used for receiving the comparison signal, counting the number of pulses of the comparison signal and outputting a count value, the count value represents a target charging mode, the control unit is connected with the output end of the counting unit and is used for outputting a control signal according to the received count value, the output parameter adjustment unit is used for receiving the control signal and adjusting an output parameter corresponding to the target charging mode according to the control signal, and the drive control circuit is used for receiving the output parameter and outputting a drive signal corresponding to the output parameter to a switching tube. The signal detection unit of the primary side control circuit receives the feedback signal and the first reference signal, and compares the feedback signal with the first reference signal to output a comparison signal. The number of pulses of the comparison signal is counted by a counting unit. The control unit determines a target charging mode based on the count value of the pulse number, and then outputs a corresponding control signal to the output parameter adjusting unit to realize the adjustment of the output parameter. Therefore, the primary side control circuit can multiplex the feedback signals output by the optocoupler, determine a target charging mode and further adjust output parameters. The drive control circuit outputs a drive signal corresponding to the output parameter to the switching tube based on the output parameter. Therefore, the primary side control circuit provided by the embodiment of the utility model does not need to be additionally provided with an output voltage detection circuit, can be compatible with the packaging structure of the existing primary side control circuit, and reduces the cost. Optionally, the number of pulses is a first type value, the control signal indicates that the target charging mode is a normal charging mode, the number of pulses is a third type value, the control signal indicates that the target charging mode is restored to the normal charging mode, the number of pulses is a second type value, the control signal indicates that the target charging mode is a fast charging mode, and the first type value, the second type value and the third type value are different and are positive integers. Optionally, the output parameter adjusting unit