Switching power supply and primary side control circuit thereof

Abstract

The utility model relates to a switching power supply and a primary side control circuit thereof, the switching power supply comprises an optical coupler and a charging protocol interaction circuit, the optical coupler is coupled with the charging protocol interaction circuit, and 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 which compares a feedback signal with a first reference signal and outputs 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 outputs 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 driving control circuit outputs a driving signal corresponding to the output parameter. According to the switching power supply and the primary side control circuit thereof provided by the utility model, an output voltage detection circuit does not need to be additionally arranged, the packaging structure of the existing primary side control circuit can be compatible, and the cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, and in particular to a switching power supply and its primary-side control circuit. Background Technology

[0002] Fast charging technology is widely used in smart electronic devices such as mobile phones. Switching power supplies that support fast charging technology are receiving increasing attention.

[0003] Traditional switching power supplies supporting fast charging require the power supply to have different voltage output capabilities and be able to adjust the output voltage to the target output voltage based on the fast charging protocol supported by the smart electronic device being charged. Traditional switching power supplies also have some shortcomings: 1) Fixed overvoltage protection (OVP) threshold, which is usually set based on the maximum output voltage; 2) Poor adaptability to power range, in low-power charging scenarios, the limit power protection point is high, which can easily trigger frequency reduction or burst mode, resulting in low charging efficiency; 3) Poor loop stability, lacking real-time output voltage detection and dynamic loop gain adjustment capabilities.

[0004] Currently, some switching power supplies that support fast charging have been developed to address the shortcomings of traditional switching power supplies. A typical approach involves adding an output voltage detection circuit to the primary-side control circuit to adaptively adjust the output voltage / charging power demand of the secondary side in real time. However, existing switching power supplies require adding an output voltage detection pin to the primary-side control chip. Utility Model Content

[0005] The purpose of this invention is at least to provide a switching power supply and its primary-side control circuit, which adjusts the output parameters of the primary-side control circuit through feedback signals.

[0006] In a first aspect, this utility model provides a primary-side control circuit for a switching power supply, comprising: a signal detection unit, which receives a feedback signal and a first reference signal, compares the feedback signal and the first reference signal, and outputs a comparison signal; a counting unit, coupled to the output terminal of the signal detection unit, which receives the comparison signal, counts the number of pulses of the comparison signal, and outputs a count value, wherein the count value represents a target charging mode; a control unit, connected to the output terminal of the counting unit, which outputs a control signal according to the received count value; an output parameter adjustment unit, which receives the control signal and adjusts the output parameters corresponding to the target charging mode according to the control signal; and a drive control circuit, which receives the output parameters and outputs a drive signal corresponding to the output parameters to the switching transistor.

[0007] The signal detection unit of the primary-side control circuit receives a feedback signal and a first reference signal, compares the feedback signal and the first reference signal to output a comparison signal. A counting unit counts the number of pulses in the comparison signal. The control unit determines the target charging mode based on the pulse count and then outputs a corresponding control signal to the output parameter adjustment unit to adjust the output parameters. Thus, the primary-side control circuit can reuse the feedback signal output from the optocoupler to determine the target charging mode and adjust the output parameters. The drive control circuit outputs a drive signal corresponding to the output parameters to the switching transistor. Therefore, the primary-side control circuit provided in this embodiment does not require an additional output voltage detection circuit, is compatible with existing primary-side control circuit packaging structures, and reduces costs.

[0008] Optionally, if the number of pulses is a first-type value, the control signal indicates that the target charging mode is a normal charging mode; if the number of pulses is a third-type value, the control signal indicates that the target charging mode has been restored to a normal charging mode; if the number of pulses is a second-type value, the control signal indicates that the target charging mode is a fast charging mode; the first-type value, the second-type value, and the third-type value are different and are positive integers.

[0009] Optionally, the output parameter adjustment unit is adapted to adjust at least one of the following output parameters: a second reference value corresponding to the loop gain, a third reference value corresponding to the output power, and a fourth reference value corresponding to the overvoltage protection.

[0010] Optionally, there are N types of fast charging modes, where N is a positive integer and N≥2.

[0011] Optionally, the signal detection unit includes a first comparator, a first input terminal of the first comparator receiving a feedback signal, a second input terminal of the first comparator receiving a first reference signal, and an output terminal of the first comparator coupled to the counting unit.

[0012] Optionally, the output parameter adjustment unit includes a loop gain adjustment unit; the loop gain adjustment unit responds to K first control signals in the control signal and adjusts the second reference value corresponding to the loop gain according to the K first control signals.

[0013] Optionally, the loop gain adjustment unit includes: K switching units, a resistor string formed by L resistors connected in series, and a second comparator. The first end of the resistor string is connected to an internal voltage source via a pull-up resistor, and the second end of the resistor string is grounded. The first input of the second comparator receives a sampling signal, and the second input of the second comparator is connected to the node between any two series resistors in the resistor string to receive a second reference value. The second comparator compares the sampling signal and the second reference value. The output of the second comparator is connected to the drive control circuit. The i-th switching unit in the K switching units is connected in parallel to the two ends of the j-th resistor in the resistor string. The control end of the i-th switching unit receives a corresponding first control signal provided by the control unit. When the first control signal corresponding to the i-th switching unit is valid, the i-th switching unit is turned on, shorting the j-th resistor. Different switching units in the K switching units are connected in parallel to the two ends of different resistors in the resistor string to adjust the second reference value. The drive control circuit drives the switching transistor. Wherein, K, L, and i are all positive integers, and 1≤i≤K, 1≤j≤L, and L>K.

[0014] Optionally, the output parameter adjustment unit includes an output power adjustment unit; the output power adjustment unit responds to M second control signals in the control signal and adjusts the third reference value corresponding to the output power according to the M second control signals.

[0015] Optionally, the output power adjustment unit includes: M switching units and a third comparator, wherein: the first input terminal of the third comparator receives a sampling signal, the second input terminal of the third comparator receives a third reference signal, the output terminal of the third comparator is connected to the drive control circuit, the first terminal of each of the M switching units receives a corresponding second control signal from the control unit, the second terminal of each of the M switching units is connected to the second input terminal of the third comparator, the third terminal of each of the M switching units receives M third reference values, and the M switching units are controlled by receiving M second control signals respectively. When the corresponding switching unit is turned on, the corresponding third reference value is used as the third reference signal of the third comparator, where M is a positive integer.

[0016] Optionally, the output parameter adjustment unit includes an overvoltage protection threshold adjustment unit; the overvoltage protection threshold adjustment unit responds to N third control signals in the control signal and outputs a fourth reference value corresponding to the overvoltage protection according to the N third control signals.

[0017] Optionally, the overvoltage protection threshold adjustment unit includes: N switching units and a fourth comparator, wherein: the first input terminal of the fourth comparator receives the power supply voltage, the second input terminal of the fourth comparator receives a fourth reference signal, the output terminal of the fourth comparator is connected to the drive control circuit, the first terminal of each of the N switching units receives a corresponding third control signal from the control unit, the second terminal of each of the N switching units is connected to the second input terminal of the fourth comparator, the third terminal of each of the N switching units receives N fourth reference values, and the N switching units are controlled by receiving N third control signals. When the corresponding switching unit is turned on, the corresponding fourth reference value is used as the fourth reference signal of the fourth comparator, where N is a positive integer.

[0018] Optionally, the primary-side control circuit further includes a zeroing unit connected to the counting unit, which outputs a zeroing signal to the counting unit when the count value is detected as a third-class value.

[0019] Optionally, the drive signal output by the drive control circuit controls the switching transistor to turn on or off.

[0020] Optionally, the signal detection unit, counting unit, control unit, output parameter adjustment unit, and drive control circuit are integrated into the same primary-side control chip.

[0021] Optionally, the primary-side control chip and the switching transistor are packaged together.

[0022] Optionally, the signal detection unit, counting unit, control unit, output parameter adjustment unit, drive control circuit, and switching transistor are integrated into the same chip.

[0023] Optionally, the primary-side control circuit's package structure includes a current sampling pin, a ground pin, a power supply pin, an output feedback pin, and a third terminal pin of the switching transistor; the first terminal of the switching transistor is connected to the drive control circuit, the second terminal of the switching transistor is connected to the sampling pin, and the third terminal of the switching transistor is connected to the third terminal pin of the switching transistor.

[0024] Optionally, the current sampling pin, ground pin, power supply pin, and output feedback pin are located on the first side of the primary-side control circuit's package structure, and the third pin of the switching transistor is located on the second side of the primary-side control circuit's package structure, with the first and second sides being parallel.

[0025] This utility model also provides a switching power supply, including an optocoupler, a charging protocol interaction circuit, and a primary-side control circuit. The optocoupler is coupled to the charging protocol interaction circuit, and the 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 includes: a signal detection unit, which receives the feedback signal and a first reference signal, compares the feedback signal and the first reference signal, and outputs a comparison signal; a counting unit, which is coupled to the output terminal of the signal detection unit, receives the comparison signal, counts the number of pulses of the comparison signal, and outputs a count value, the count value representing the target charging mode; a control unit, which is connected to the output terminal of the counting unit, and outputs a control signal according to the received count value; an output parameter adjustment unit, which receives the control signal and adjusts the output parameters corresponding to the target charging mode according to the control signal; and a drive control circuit, which receives the output parameters and outputs a drive signal corresponding to the output parameters to the switching transistor.

[0026] Optionally, the count value is a first type of value, indicating that the target charging mode is a normal charging mode; the count value is a third type of value, indicating that the target charging mode has been restored to a normal charging mode; the count value is a second type of value, indicating that the target charging mode is a fast charging mode; the first type of value, the second type of value, and the third type of value are different and are positive integers.

[0027] Optionally, the output parameter adjustment unit is adapted to adjust at least one of the following output parameters: a second reference value corresponding to the loop gain, a third reference value corresponding to the output power, and a fourth reference value corresponding to the overvoltage protection.

[0028] Optionally, there are N types of fast charging modes, where N is a positive integer and N≥2.

[0029] Optionally, the signal detection unit includes a first comparator, a first input terminal of the first comparator receiving a feedback signal, a second input terminal of the first comparator receiving a first reference signal, and an output terminal of the first comparator coupled to the counting unit.

[0030] Optionally, the output parameter adjustment unit includes a loop gain adjustment unit; the loop gain adjustment unit responds to K first control signals in the control signal and adjusts the second reference value corresponding to the loop gain according to the K first control signals.

[0031] Optionally, the loop gain adjustment unit includes: K switching units, a resistor string formed by L resistors connected in series, and a second comparator. The first end of the resistor string is connected to an internal voltage source via a pull-up resistor, and the second end of the resistor string is grounded. The first input of the second comparator receives a sampling signal, and the second input of the second comparator is connected to the node between any two series resistors in the resistor string to receive a second reference value. The second comparator compares the sampling signal and the second reference value. The output of the second comparator is connected to the drive control circuit. The i-th switching unit in the K switching units is connected in parallel to the two ends of the j-th resistor in the resistor string. The control end of the i-th switching unit receives a corresponding first control signal provided by the control unit. When the first control signal corresponding to the i-th switching unit is valid, the i-th switching unit is turned on, shorting the j-th resistor. Different switching units in the K switching units are connected in parallel to the two ends of different resistors in the resistor string to adjust the second reference value. The drive control circuit drives the switching transistor. Wherein, K, L, and i are all positive integers, and 1≤i≤K, 1≤j≤L, and L>K.

[0032] Optionally, the output parameter adjustment unit includes an output power adjustment unit; the output power adjustment unit responds to M second control signals in the control signal and adjusts the third reference value corresponding to the output power according to the M second control signals.

[0033] Optionally, the output power adjustment unit includes: M switching units and a third comparator, wherein: the first input terminal of the third comparator receives a sampling signal, the second input terminal of the third comparator receives a third reference signal, the output terminal of the third comparator is connected to the drive control circuit, the first terminal of each of the M switching units receives a corresponding second control signal from the control unit, the second terminal of each of the M switching units is connected to the second input terminal of the third comparator, the third terminal of each of the M switching units receives M third reference values, and the M switching units are controlled by receiving M second control signals respectively. When the corresponding switching unit is turned on, the corresponding third reference value is used as the third reference signal of the third comparator, where M is a positive integer.

[0034] Optionally, the output parameter adjustment unit includes an overvoltage protection threshold adjustment unit; the overvoltage protection threshold adjustment unit responds to N third control signals in the control signal and outputs a fourth reference value corresponding to the overvoltage protection according to the N third control signals.

[0035] Optionally, the overvoltage protection threshold adjustment unit includes: N switching units and a fourth comparator, wherein: the first input terminal of the fourth comparator receives the power supply voltage, the second input terminal of the fourth comparator receives a fourth reference signal, the output terminal of the fourth comparator is connected to the drive control circuit, the first terminal of each of the N switching units receives a corresponding third control signal from the control unit, the second terminal of each of the N switching units is connected to the second input terminal of the fourth comparator, the third terminal of each of the N switching units receives N fourth reference values, and the N switching units are controlled by receiving N third control signals. When the corresponding switching unit is turned on, the corresponding fourth reference value is used as the fourth reference signal of the fourth comparator, where N is a positive integer.

[0036] Optionally, the primary-side control circuit further includes a clearing unit connected to the counting unit, which outputs a clearing signal to the counting unit when the number of pulses detected is a third-type value.

[0037] Optionally, the drive signal output by the drive control circuit controls the switching transistor to turn on or off.

[0038] Optionally, the signal detection unit, counting unit, control unit, output parameter adjustment unit, and drive control circuit are integrated into the same primary-side control chip.

[0039] Optionally, the primary-side control chip and the switching transistor are packaged together.

[0040] Optionally, the signal detection unit, counting unit, control unit, output parameter adjustment unit, drive control circuit, and switching transistor are integrated into the same chip.

[0041] Optionally, the primary-side control circuit's package structure includes a current sampling pin, a ground pin, a power supply pin, an output feedback pin, and a third terminal pin of the switching transistor; the first terminal of the switching transistor is connected to the drive control circuit, the second terminal of the switching transistor is connected to the sampling pin, and the third terminal of the switching transistor is connected to the third terminal pin of the switching transistor.

[0042] Optionally, the current sampling pin, ground pin, power supply pin, and output feedback pin are located on the first side of the primary-side control circuit's package structure, and the third pin of the switch is located on the second side of the primary-side control circuit's package structure, with the first and second sides being parallel.

[0043] Optionally, the first end of the optocoupler is coupled to the charging protocol interaction circuit, the second end of the optocoupler is coupled to the output end of the switching power supply, the third end of the optocoupler is coupled to the primary-side control circuit, and the fourth end of the optocoupler is grounded; the output signal of the charging protocol interaction circuit is transmitted to the receiving end of the feedback signal of the primary-side control circuit through the optocoupler, and the fourth end of the optocoupler is connected to the current sampling pin of the primary-side control circuit through a resistor.

[0044] Optionally, the charging protocol interaction circuit includes: a charging protocol interaction unit and a switching unit, wherein: the charging protocol interaction unit is coupled to the charging interface circuit, and in response to the identified target charging mode, outputs a fourth control signal to the control terminal of the switching unit; the first terminal of the switching unit is coupled to the first ground terminal of the optocoupler, and the second terminal of the switching unit is grounded; the fourth control signal controls the number of times the switching unit is turned on, and the number of times the switching unit is turned on is related to the target charging mode.

[0045] Optionally, the charging interface circuit interacts with the smart electronic device via a charging protocol to determine whether the switching power supply supports the fast charging mode of the smart electronic device.

[0046] Optionally, the charging protocol interaction unit is connected between the output voltage of the switching power supply and ground. Attached Figure Description

[0047] Figure 1 This is a circuit diagram of a switching power supply according to an embodiment of the present invention;

[0048] Figure 2 This is a circuit diagram of a primary-side control circuit in one embodiment of this utility model;

[0049] Figure 3 This is a circuit diagram of a loop gain adjustment unit of a primary-side control circuit in an embodiment of this utility model;

[0050] Figure 4 This is a circuit diagram of the output power adjustment unit of a primary-side control circuit in an embodiment of this utility model;

[0051] Figure 5 This is a circuit diagram of an overvoltage protection threshold adjustment unit of a primary-side control circuit in an embodiment of this utility model.

[0052] Figure 6 This is a schematic diagram of the structure of a primary-side control circuit in one embodiment of the present invention;

[0053] Figure 7 This is a timing waveform diagram of the charging process of a primary-side control circuit in an embodiment of this utility model. Detailed Implementation

[0054] As mentioned in the background section, some existing switching power supplies that support fast charging add an additional output voltage detection circuit to the primary-side control circuit. This output voltage detection circuit analyzes the secondary-side output voltage / charging power demand in real time and then performs adaptive adjustment. However, existing primary-side control circuits require an additional output voltage detection pin to be added to the primary-side control chip.

[0055] In this embodiment of the invention, the primary-side control circuit can determine the charging mode based on the feedback signal output by the charging protocol interaction circuit and the optocoupler, and then adjust the output parameters without the need for an additional output voltage detection circuit. Therefore, it can be compatible with the existing primary-side control circuit packaging structure, reducing costs.

[0056] To make the above-mentioned objectives, features and beneficial effects of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0057] In this embodiment of the utility model, the switching power supply includes: a primary-side control circuit 101, a charging protocol interaction circuit 103, and an optocoupler 102.

[0058] This utility model embodiment provides a switching power supply, see reference. Figure 1 .

[0059] In this embodiment of the invention, the optocoupler 102 is coupled to the output terminal of the switching power supply, the charging protocol interaction circuit 103, and the primary-side control circuit 101.

[0060] Specifically, the second terminal of optocoupler 102 is coupled to the output terminal of the switching power supply, receiving the output voltage VOUT of the switching power supply; the first terminal of optocoupler 102 is coupled to the charging protocol interaction circuit 103; the third terminal of optocoupler 102 is coupled to the primary-side control circuit 101; and the fourth terminal of optocoupler 102 is grounded. The output signal of the charging protocol interaction circuit 103 is transmitted to the primary-side control circuit as a feedback signal FB after passing through optocoupler 102; the fourth terminal of optocoupler 102 is connected to the current sampling pin of the primary-side control circuit via a resistor, and a capacitor is connected between the third and fourth terminals of the optocoupler.

[0061] In a specific implementation, the charging protocol interaction circuit 103 may include: a charging protocol interaction unit and a switching unit, wherein:

[0062] The charging protocol interaction unit is coupled to the charging interface circuit and, in response to the identified target charging mode, outputs a fourth control signal to the control terminal of the switching unit.

[0063] The switching unit has its first terminal coupled to the first terminal of the optocoupler and its second terminal grounded. The fourth control signal controls the number of times the switching unit is turned on, and the number of times the switching unit is turned on is related to the target charging mode.

[0064] In practice, the charging interface circuit can interact with the smart electronic device via charging protocol to determine whether the switching power supply supports the fast charging mode of the smart electronic device.

[0065] In practice, the charging protocol interaction unit can be connected between the output voltage VOUT of the switching power supply and ground.

[0066] In practical implementation, the specific principles and processes of the charging protocol interaction unit and the intelligent electronic device in exchanging charging protocols can be found in the relevant content of existing fast charging protocols, and will not be elaborated here.

[0067] If the charging protocol interaction circuit 103 determines that the switching power supply supports fast charging of smart electronic devices, then the fast charging mode of the smart electronic devices can be used as the target charging mode; if the charging protocol interaction circuit 103 determines that the switching power supply does not support fast charging mode of smart electronic devices, then the normal charging mode can be used as the target charging mode.

[0068] The aforementioned normal charging mode, also known as low-speed charging mode or low-power charging mode, refers to the state of the switching power supply when it is in normal charging mode. In some embodiments, the corresponding output voltage is 5V and the output current is 2A. In other embodiments, the corresponding output voltage is 5V and the output current is 1A.

[0069] For example, a smart electronic device supports Fast Charging Mode 2. The input voltage of the smart electronic device is 9V, and the input current is 2A. If the switching power supply supports Fast Charging Mode 2 and can output a 9V output voltage and a 2A output current, then the charging protocol interaction circuit determines Fast Charging Mode 2 as the target charging mode. If the switching power supply does not support Fast Charging Mode 2, then the charging protocol interaction circuit determines the normal charging mode as the target charging mode, with an output voltage of 5V and an output current of 2A.

[0070] In this embodiment of the invention, the charging protocol interaction circuit controls the switching unit to be turned on or off via a control signal output by the charging protocol interaction unit. When the switching unit is turned on, the first terminal of the optocoupler 102 is directly connected to the ground terminal, so the output signal of the third terminal of the optocoupler 102 causes the feedback signal FB to be quickly pulled low, forming a falling edge. Subsequently, when the switching unit is turned off, the first terminal of the optocoupler 102 is disconnected from the direct connection with the ground terminal, and under the control of the system loop, the feedback signal FB is quickly pulled up. During one turn-on and turn-off process of the switching unit, a pulse is generated in the feedback signal FB.

[0071] For different target charging modes, a corresponding number of pulses can be preset, and the pulse signals are counted. The count value corresponds one-to-one with the target charging mode. For example, if the charging mode is normal charging mode, the corresponding pulse count value is 1; if the charging mode is fast charging mode 1, the corresponding pulse count value is 2; if the charging mode is fast charging mode 2, the corresponding pulse count value is 3, and so on.

[0072] In this embodiment of the utility model, the switching power supply also includes other circuit structures, such as a rectifier bridge circuit 104, a primary winding 105, a secondary winding 106, an auxiliary winding 107, etc.

[0073] Specifically, the working principle, connection relationship, and specific circuit structure of the rectifier bridge circuit 104, primary winding 105, secondary winding 106, and auxiliary winding 107 can all be found in the relevant content of existing switching power supplies.

[0074] This utility model embodiment provides a primary-side control circuit for a switching power supply, referring to... Figure 2 A schematic diagram of the structure of a primary-side control circuit in an embodiment of this utility model is provided.

[0075] In this embodiment of the invention, the primary-side control circuit 101 includes: a signal detection unit 1011, a counting unit 1012, a control unit 1013, an output parameter adjustment unit 1014, and a drive control unit 51, wherein:

[0076] The signal detection unit 1011 is coupled to the third terminal of the optocoupler 102. Its first input terminal receives the feedback signal FB, its second input terminal receives the first reference signal, and its output terminal outputs the comparison signal.

[0077] The counting unit 1012 is connected to the output terminal of the signal detection unit 1011 and is used to count the number of pulses in the comparison signal and output the count value, which represents the target charging mode.

[0078] The control unit 1013 is connected to the output terminal of the counting unit 1012 and outputs a control signal according to the received count value;

[0079] The output parameter adjustment unit 1014 receives a control signal and adjusts the output parameters corresponding to the target charging mode according to the control signal.

[0080] The drive control circuit 51 receives the output parameters and outputs a drive signal corresponding to the output parameters to the switching transistor.

[0081] In practice, if the count value is of the first type (e.g., binary number 001), the target charging mode is normal charging mode; if the count value is of the third type (e.g., binary number 110), the target charging mode is restored to normal charging mode; if the count value is of the second type, the target charging mode is fast charging mode; the first, second, and third types of values ​​are different and are all positive integers.

[0082] In practice, there are N types of fast charging modes, where N is a positive integer and N≥2.

[0083] For example, the first class has a value of 1, the second class has values ​​of 2, 3, 4, and 5, and the third class has a value of 6.

[0084] As in the example above, the second category values ​​are 2, 3, 4, and 5. When the count value is 2, the corresponding target charging mode is fast charging mode 1; when the count value is 3, the corresponding target charging mode is fast charging mode 2; when the count value is 4, the corresponding target charging mode is fast charging mode 3; and when the count value is 5, the corresponding target charging mode is fast charging mode 4.

[0085] In specific implementations, the output parameters include at least one of the following: loop gain, output power, and overvoltage protection threshold. The fast charging mode differs from the normal charging mode in at least one of the following: output power, loop gain, and overvoltage protection threshold.

[0086] In practice, for different target charging modes, the corresponding output parameters can be completely different, or they can be partially the same and partially different (i.e., not completely the same).

[0087] In a specific implementation, the output parameter adjustment unit 1014 can adjust at least one of the following output parameters: the second reference value corresponding to the loop gain, the third reference value corresponding to the output power, and the fourth reference value corresponding to the overvoltage protection.

[0088] In practice, the loop gain adjustment unit 20 can be used to adjust the second reference value corresponding to the loop gain; the output power adjustment unit 30 can be used to adjust the third reference value corresponding to the output power; and the overvoltage protection threshold adjustment unit 40 can be used to adjust the fourth reference value corresponding to the overvoltage protection.

[0089] In some embodiments, the output parameter adjustment unit 1014 includes a loop gain adjustment unit 20, an output power adjustment unit 30, and an overvoltage protection threshold adjustment unit 40, which adjusts the second reference value corresponding to the loop gain, the third reference value corresponding to the output power, and the fourth reference value corresponding to the overvoltage protection.

[0090] In some embodiments, corresponding to the normal charging mode, the charging voltage is 5V, the charging current is 2A, the count value is the first type value 001, the second reference value corresponding to the loop gain adjustment unit is AV1, the third reference value corresponding to the output power adjustment unit is Vref1, and the fourth reference value corresponding to the overvoltage protection threshold adjustment unit is OVP1.

[0091] When the charging mode is reset, the charging voltage is 5V, the charging current is 4A, the count value is the third type value 110, the charging mode is restored to normal charging mode, the second reference value corresponding to the loop gain adjustment unit is AV1, the third reference value corresponding to the output power adjustment unit is Vref1, and the fourth reference value corresponding to the overvoltage protection threshold adjustment unit is OVP1.

[0092] The corresponding charging mode is fast charging mode one, the charging voltage is 9V, the charging current is 2A, the count value is the second type value 010, the second reference value corresponding to the loop gain adjustment unit is AV2, the third reference value corresponding to the output power adjustment unit is Vref2, and the fourth reference value corresponding to the overvoltage protection threshold adjustment unit is OVP1.

[0093] The corresponding charging mode is fast charging mode 2, the charging voltage is 9V, the charging current is 2A, the count value is the second type value 011, the second reference value corresponding to the loop gain adjustment unit is AV2, the third reference value corresponding to the output power adjustment unit is Vref2, and the fourth reference value corresponding to the overvoltage protection threshold adjustment unit is OVP2.

[0094] The corresponding charging mode is fast charging mode 3, the charging voltage is 12V, the charging current is 1.5A, the count value is the second type value 100, the second reference value corresponding to the loop gain adjustment unit is AV2, the third reference value corresponding to the output power adjustment unit is Vref2, and the fourth reference value corresponding to the overvoltage protection threshold adjustment unit is OVP3.

[0095] The corresponding charging mode is fast charging mode four, the charging voltage is 20V, the charging current is 1.5A, the count value is the second type value 101, the second reference value corresponding to the loop gain adjustment unit is AV2, the third reference value corresponding to the output power adjustment unit is Vref3, and the fourth reference value corresponding to the overvoltage protection threshold adjustment unit is OVP4.

[0096] In a specific implementation, the signal detection unit is a first comparator 1011. The first input terminal of the first comparator 1011 receives the feedback signal FB, the second input terminal of the first comparator 1011 receives the first reference signal, and the output terminal of the first comparator 1011 is coupled to the counting unit 1012.

[0097] When the feedback signal FB is at a level signal stage, the voltage value of the feedback signal FB is greater than that of the first reference signal; when the feedback signal FB is at a falling edge, the voltage value of the region where the falling edge is located is less than that of the first reference signal.

[0098] The first comparator 1011 compares the voltage value of the feedback signal FB with the voltage value of the first reference signal. When the feedback signal FB is a falling edge, the first comparator 1011 outputs a low-level signal. The counting unit 1012 determines the number of pulses in the comparison signal based on the number of low-level signals output by the first comparator 1011.

[0099] In specific implementations, the aforementioned first reference signal can be a first reference voltage. The first reference voltage can be set based on the specific application scenario. In some embodiments, the first reference voltage can be set to 200 millivolts (mV). It is understood that the aforementioned first reference voltage can also be other values, as long as a falling edge can be detected from the feedback signal FB.

[0100] In this embodiment of the present invention, the output parameter adjustment unit 1014 may include a loop gain adjustment unit 20, which can adjust the gain impedance value of the loop gain network to the second reference value corresponding to the loop gain based on the received K first control signals ctr_Av.

[0101] The control unit 1013 can determine the target gain impedance value corresponding to the target charging mode based on the target charging mode. Then, the control unit 1013 outputs K first control signals ctr_Av from the control signal to the loop gain adjustment unit 20, adjusting the equivalent resistance of the loop gain adjustment unit 20 to the target gain impedance value, thereby realizing the adjustment of the second reference value corresponding to the loop gain.

[0102] In a specific implementation, the loop gain adjustment unit 20 includes K switching units, a resistor string formed by L resistors connected in series, and a second comparator 21, wherein:

[0103] The first input terminal of the second comparator 21 receives the sampling signal, and the second input terminal of the second comparator 21 is connected to the node between any two series resistors in the resistor string to receive the second reference value. The output terminal of the second comparator 21 is connected to the drive control circuit 51. The second comparator 21 compares the sampling signal with the second reference value and outputs the comparison result to the drive control circuit 51. The drive circuit can be used to drive the switching transistor 52.

[0104] The i-th switch unit in a series of K switch units is connected across the j-th resistor in a parallel resistor string. The control terminal of the i-th switch unit receives a corresponding first control signal from the control unit. When the first control signal input to the control terminal of the i-th switch unit is valid, the i-th switch unit is turned on, and the j-th resistor is short-circuited. Thus, by connecting different resistors in the parallel resistor string to different switch units in the series of K switch units, and controlling the different switch units to turn on via the first control signal, the second reference value is adjusted. K, L, and i are all positive integers, and 1 ≤ i ≤ K, 1 ≤ j ≤ L, and L > K.

[0105] In some embodiments, "first control signal valid" can mean that the first control signal is at a high level. That is, when the control terminal of the i-th switch unit receives a high-level first control signal, the first control signal input to the control terminal of the i-th switch unit is valid; when the control terminal of the i-th switch unit receives a low-level first control signal, the first control signal input to the control terminal of the i-th switch unit is invalid.

[0106] In practice, the resistance values ​​of all resistors in the above resistor string can be equal or unequal. Alternatively, the resistance values ​​of some resistors can be equal, while the remaining values ​​are unequal.

[0107] After determining the target gain impedance value, the control unit 1013 outputs a first control signal ctr_Av to the K switching units. Among the K switching units, the first control signal ctr_Av corresponding to some of the switching units is valid, that is, the first control signal ctr_Av corresponding to some of the switching units is at a high level; after the first terminal of the aforementioned switching units receives the high-level first control signal ctr_Av, it is turned on, thereby adjusting the second reference value.

[0108] By adjusting the equivalent resistance of the loop gain adjustment unit 20, a second reference value for the target gain impedance value corresponding to the target charging mode is obtained.

[0109] In a practical implementation, each of the K switching units can be a MOSFET. Accordingly, in the K switching units, the first terminal of the switching unit is the gate of the MOSFET; the second terminal of the switching unit is the drain of the MOSFET; and the third terminal of the switching unit is the source of the MOSFET.

[0110] In some embodiments, all K switching units can be PMOS transistors. In other embodiments, all K switching units can be NMOS transistors.

[0111] Reference Figure 3 A schematic diagram of the loop gain adjustment unit 20 of a primary-side control circuit according to an embodiment of this utility model is given below. Figure 3The working principle of the loop gain adjustment unit 20 will be explained.

[0112] Figure 3 In the circuit, the loop gain adjustment unit 20 includes two switching units, a resistor string formed by four resistors connected in series, and a second comparator 21. The two switching units are MOSFETs Q1 and Q2, respectively. The resistor string includes four resistors connected in series: resistor R1, resistor R2, resistor R3, and resistor R4, wherein:

[0113] The first end of the first resistor R1 is the first end of the resistor string. The first end of the first resistor R1 is connected to the internal voltage source AVDD through the pull-up resistor R5. The internal voltage source AVDD is associated with the input power supply voltage VCC. The second end of the first resistor R1 is connected to the first end of the second resistor R2. The second end of the second resistor R2 is connected to the first end of the third resistor R3. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is the second end of the resistor string and is grounded.

[0114] The drain of MOSFET Q1 is connected to the first terminal of the second resistor R2, and the source of MOSFET Q1 is connected to the second terminal of the second resistor R2.

[0115] The drain of MOSFET Q2 is coupled to the second terminal of the second resistor R2, and the source of MOSFET Q2 is connected to the second terminal of the third resistor R3.

[0116] When both the control terminals of MOSFET Q1 and MOSFET Q2 receive a high-level first control signal ctr_Av, both MOSFETs Q1 and Q2 are turned on, the equivalent resistance of the resistor string is R1+R4, and the corresponding loop gain is Av1. When only the control terminal of MOSFET Q1 receives a high-level first control signal ctr_Av, the equivalent resistance of the resistor string is R1+R3+R4, and the corresponding loop gain is Av2. When only the control terminal of MOSFET Q2 receives a high-level first control signal ctr_Av, the equivalent resistance of the resistor string is R1+R2+R4, and the corresponding loop gain is Av3. When neither the control terminal of MOSFET Q1 nor the control terminal of MOSFET Q2 receives a high-level first control signal ctr_Av, both MOSFETs Q1 and Q2 are turned off, the equivalent resistance of the resistor string is R1+R2+R3+R4, and the corresponding loop gain is Av4.

[0117] The first input terminal of the second comparator 21 receives the sampling signal CS, and the second input terminal is connected to the second terminal of the MOS transistor Q1. The first input terminal of the second comparator 21 receives the sampling signal CS, and the output terminal of the second comparator 21 is connected to the drive control circuit 51. The drive control circuit 51 is used to drive the switching transistor 52.

[0118] In specific implementations, the first input terminal of the second comparator 21 can be a positive input terminal, and the second input terminal of the second comparator 21 can be an inverting input terminal. The second comparator 21 can be a commonly used comparator, or other devices capable of implementing comparison functions, or a circuit structure capable of implementing comparison functions.

[0119] In a specific implementation, the loop gain adjustment unit 20 may further include a diode D1, which is coupled between the second end of the pull-up resistor R5 and the first end of the first resistor R1; the first end of the pull-up resistor R5 is connected to the internal voltage source AVDD, and the second end of the pull-up resistor R5 is also input with a feedback signal FB.

[0120] Therefore, by selecting the switching unit that is turned on in the loop gain adjustment unit through the control unit, the equivalent resistance value of the loop gain network can be adjusted, thereby achieving the adjustment of the loop gain.

[0121] In this embodiment of the invention, the output parameter adjustment unit includes an output power adjustment unit 30. Based on M second control signals ctr_Vref received from the control signals, the output power adjustment unit 30 outputs a third reference value corresponding to the target charging mode. This third reference value is associated with the output power of the switching power supply. By adjusting the third reference value, the third reference value of the output power of the switching power supply is adjusted.

[0122] In a specific implementation, the output power adjustment unit includes: M switching units and a third comparator 31, wherein:

[0123] The first input terminal of the third comparator 31 receives the sampling signal CS, the second input terminal of the third comparator 31 receives the third reference value, and the output terminal of the third comparator 31 is connected to the drive control circuit 51.

[0124] The first terminal of each of the M switching units receives a corresponding second control signal ctr_Vref from the control unit. The second terminal of each of the M switching units is connected to the second input terminal of the third comparator 31. The third terminal of each of the M switching units receives its corresponding third reference value. The M switching units are controlled by the M second control signals ctr_Vref. When some of the switching units receive the corresponding high-level second control signal ctr_Vref, they are turned on. The turned-on switching units use the corresponding third reference value as the third reference signal of the third comparator. M is a positive integer.

[0125] In practice, different switching units correspond to different third reference values. The control unit can determine the third reference value corresponding to the target charging mode based on the target charging mode, and then output a second control signal ctr_Vref of the corresponding level to M switching units 301; the corresponding switching unit that receives the high-level second control signal ctr_Vref is turned on, realizing the output of the corresponding third reference value.

[0126] For example, the output power adjustment unit 30 includes three switching units. The third reference value corresponding to the third terminal input of the first switching unit is Vref1, the third reference value corresponding to the third terminal input of the second switching unit is Vref2, and the third reference value corresponding to the third terminal input of the third switching unit is Vref3.

[0127] The target charging mode is charging mode 2, and the third reference value corresponding to charging mode 2 is Vref2. The control unit outputs a high-level second control signal ctr_Vref to the first terminal of the switching unit 22, and the third terminal of the switching unit 22 outputs the corresponding third reference value Vref2.

[0128] In a practical implementation, each of the M switching units can be a MOSFET. The first terminal of the M switching units is the gate of the M MOSFETs; the second terminal of the M switching units is the drain of the M MOSFETs; and the third terminal of the switching units is the source of the M MOSFETs.

[0129] In some embodiments, all M switching units can be PMOS transistors. In other embodiments, all M switching units can be NMOS transistors.

[0130] Reference Figure 4 A schematic diagram of the output power adjustment unit 30 of a primary-side control circuit in an embodiment of this utility model is provided.

[0131] Figure 4 In the output power adjustment unit 30, there are three switching units, namely MOSFET Q3, MOSFET Q4 and MOSFET Q5, in sequence:

[0132] The gate of MOSFET Q3 is coupled to the control unit, the source of MOSFET Q3 is input to the third reference value Vref1, and the drain of MOSFET Q3 is coupled to the output terminal of the output power adjustment unit 30.

[0133] The gate of MOSFET Q4 is coupled to the control unit, the source of MOSFET Q4 is input to the third reference value Vref2, and the drain of MOSFET Q4 is coupled to the output terminal of the output power adjustment unit 30.

[0134] The gate of MOSFET Q5 is coupled to the control unit, the source of MOSFET Q5 is input to the third reference value Vref3, and the drain of MOSFET Q5 is coupled to the output terminal of the output power adjustment unit 30. The corresponding third reference value Vref1 is less than the corresponding third reference value Vref2, and the corresponding third reference value Vref2 is less than the corresponding third reference value Vref3.

[0135] If the control unit determines the third reference value Vref2 corresponding to the sampling signal based on the target charging mode, the control unit outputs a high-level second control signal ctr_Vref to the gate of MOSFET Q4. MOSFET Q4 turns on when the high-level second control signal ctr_Vref is input to its gate, and outputs the third reference value Vref2 to the second input terminal of the third comparator 31.

[0136] The sampling signal is input to the first input terminal of the third comparator 31, the corresponding third reference value is input to the second input terminal of the third comparator 31, and the output terminal of the third comparator 31 is coupled to the drive control circuit 51 of the switching power supply. The drive control circuit 51 is coupled to the switching transistor 52 of the switching power supply and is used to drive the switching transistor 52.

[0137] In a practical implementation, the sampling signal can be correlated with the voltage value of the feedback signal. Specifically, an impedance element can be set between the output terminal of the optocoupler 102 and the first input terminal of the third comparator 31, and the current flowing through the impedance element can be used as the sampling signal.

[0138] In a specific implementation, the first input terminal of the third comparator 31 can be a positive input terminal, and the second input terminal of the third comparator 31 can be an inverting input terminal. The third comparator 31 can be a commonly used comparator, or other devices capable of implementing comparison functions, or a circuit structure capable of implementing comparison functions.

[0139] In this embodiment of the invention, the output parameter adjustment unit may include an overvoltage protection threshold adjustment unit 40. The overvoltage protection threshold adjustment unit 40 can output a corresponding fourth reference value based on N third control signals ctr_OVP received from the control signals. This fourth reference value is associated with the overvoltage protection threshold of the switching power supply. Specifically, the overvoltage protection threshold of the switching power supply is the fourth reference value.

[0140] Therefore, by using different fourth reference values, the overvoltage protection threshold of the switching power supply can be controlled.

[0141] In a specific implementation, the overvoltage protection threshold adjustment unit 40 may include N switching units and a fourth comparator 41.

[0142] In a specific implementation, the first input terminal of the fourth comparator 41 receives the power supply voltage VCC, the second input terminal of the fourth comparator 41 receives the fourth reference value, and the output terminal of the fourth comparator 41 is connected to the drive control circuit 51.

[0143] For each of the N switching units, its first terminal receives a corresponding third control signal from the control unit, its second terminal is connected to the second input terminal of the fourth comparator 41, and its third terminal receives a fourth reference value. The N switching units are controlled by N third control signals. When a portion of the switching units receives a high-level third control signal at its first terminal, it is turned on, and the corresponding fourth reference value serves as the fourth reference signal for the fourth comparator 41. N is a positive integer.

[0144] In practice, different switching units correspond to different fourth reference values. The control unit can determine the fourth reference value corresponding to the target charging mode. Then, the control unit outputs a third control signal ctr_OVP of the corresponding level to N switching units; the corresponding switching unit that receives the high-level third control signal ctr_OVP is turned on, realizing the output of the corresponding fourth reference value.

[0145] For example, the overvoltage protection threshold adjustment unit 40 includes three switching units, wherein the fourth reference value corresponding to the third terminal input of the first switching unit is OVP1, the fourth reference value corresponding to the third terminal input of the second switching unit is OVP2, and the fourth reference value corresponding to the third terminal input of the second switching unit is OVP3.

[0146] The target charging mode is charging mode 2, and the corresponding fourth reference value is OVP2. The control unit outputs a high-level third control signal to the first terminal of the second switching unit 22. The second switching unit is turned on, and the corresponding fourth reference value OVP2 is output through the third terminal of the second switching unit.

[0147] In practical implementation, each of the N switching units can be a MOSFET. The first terminal of the switching unit is the gate of the M MOSFETs; the second terminal of the N switching units is the source / drain of the M MOSFETs; and the third terminal of the switching unit is the drain / source of the MOSFETs.

[0148] In some embodiments, all N switching units can be PMOS transistors. In other embodiments, all N switching units can be NMOS transistors.

[0149] In a specific implementation, the first input terminal of the aforementioned fourth comparator 41 can be a positive input terminal, and the second input terminal of the fourth comparator 41 can be an inverting input terminal. The aforementioned fourth comparator 41 can be a commonly used comparator, or other devices capable of implementing comparison functions, or a circuit structure capable of implementing comparison functions.

[0150] Reference Figure 5 A schematic diagram of the overvoltage protection threshold adjustment unit 40 of a primary-side control circuit according to an embodiment of this utility model is given below. Figure 5 The working principle of the overvoltage protection threshold adjustment unit 40 is explained.

[0151] Figure 5 In the middle, the overvoltage protection threshold adjustment unit 40 includes four switching units, namely MOSFET Q6, MOSFET Q7, MOSFET Q8 and MOSFET Q9, wherein:

[0152] The gate of MOSFET Q6 is coupled to the control unit, the source of MOSFET Q6 is input to the fourth reference value OVP1, and the drain of MOSFET Q6 is coupled to the output terminal of the overvoltage protection threshold adjustment unit 40.

[0153] The gate of MOSFET Q7 is coupled to the control unit, the source of MOSFET Q7 is input to the fourth reference value OVP2, and the drain of MOSFET Q7 is coupled to the output terminal of the output power adjustment unit 30.

[0154] The gate of MOSFET Q8 is coupled to the control unit, the source of MOSFET Q8 is input to the fourth reference value OVP3, and the drain of MOSFET Q8 is coupled to the output terminal of the output power adjustment unit 30.

[0155] The gate of MOSFET Q9 is coupled to the control unit, the source of MOSFET Q9 is input to the fourth reference value OVP4, and the drain of MOSFET Q9 is coupled to the output terminal of the overvoltage protection threshold adjustment unit 40.

[0156] The fourth reference value OVP1 is less than the fourth reference value OVP2, the fourth reference value OVP2 is less than the fourth reference value OVP3, and the fourth reference value OVP3 is less than the fourth reference value OVP4.

[0157] If the control unit 1013 determines the fourth reference value OVP2 based on the target charging mode, the control unit 1013 outputs a high-level third control signal to the gate of the MOSFET Q7. When the MOSFET Q7 receives the high-level third control signal at its gate, it turns on and outputs the fourth reference value OVP2 to the second input terminal of the fourth comparator 41.

[0158] In a specific implementation, the primary-side control circuit 101 may further include a clearing unit 1016, which may be coupled to the counting unit 1012. When the number of pulses detected exceeds a preset value, the counting unit 1012 clears the number of pulses counted by the counting unit 1012. The aforementioned preset value is not equal to the number of pulses corresponding to any charging mode supported by the switching power supply.

[0159] For example, the switching power supply supports a normal charging mode and four fast charging modes. The normal charging mode corresponds to 1 pulse, while the four fast charging modes correspond to 2 to 5 pulses respectively. The preset value is 6. When the clearing unit 1016 detects that the pulse count obtained by the counting unit 1012 is 6, it outputs a clearing signal to the counting unit 1012 to clear the pulse count counted by the counting unit 1012 to zero.

[0160] The working principle of the primary-side control circuit described above will be illustrated by specific examples below.

[0161] Table 1 shows a mapping table between charging mode and pulse count, output parameters, and count value.

[0162]

[0163] Table 1

[0164] In Table 1, taking fast charging mode 1 as an example, the output voltage is 5V, the output current is 4A, corresponding to 2 pulses, the second reference value is Av1, the third reference value is Vref1, and the fourth reference value is OVP1.

[0165] The charging protocol interaction unit identifies that the currently charging smart electronic device only supports normal charging mode. The charging protocol interaction unit outputs a control signal ctr2, controlling the switching unit in the charging protocol interaction circuit 103 to perform a turn-on / off process. A pulse exists in the feedback signal output by the optocoupler. The signal detection unit detects a falling edge in the feedback signal and outputs a low-level signal to the counting unit. The counting unit receives a low-level signal and updates the count value to 001. The control unit detects the count value as 001 and determines that the target charging mode is normal charging mode. The control unit outputs a control signal. The loop gain adjustment unit 20 adjusts the second reference value to Av1 based on the first control signal ctr_Av; the output power adjustment unit 30 adjusts the third reference value to Vref1 based on the second control signal ctr_Vref; and the overvoltage protection threshold adjustment unit 40 adjusts the fourth reference value to OVP1 based on the third control signal ctr_OVP.

[0166] The charging protocol interaction circuit 103 identifies that the currently charging smart electronic device supports fast charging mode 1. The charging protocol interaction unit outputs a control signal ctr2, controlling the switching unit in the charging protocol interaction circuit 103 to perform two on / off processes. The feedback signal FB output by the optocoupler has two falling edges. The signal detection unit 1011 detects the two falling edges in the feedback signal FB, and therefore outputs two low-level signals to the counting unit 1012. The counting unit 1012 receives the two low-level signals and updates the count value to 010. The control unit 1013 detects the count value as 010 and determines that the target charging mode is fast charging mode 1. The control unit 1013 outputs a control signal. The loop gain adjustment unit 20 adjusts the second reference value to Av2 based on the first control signal ctr_Av; the output power adjustment unit 30 adjusts the third reference value to Vref2 based on the second control signal ctr_Vref; and the overvoltage protection threshold adjustment unit 40 adjusts the fourth reference value to OVP1 based on the third control signal ctr_OVP.

[0167] And so on.

[0168] If the count value of the counting unit is updated to 110, the switching power supply is determined to enter reset mode. The control unit outputs control signals. The loop gain adjustment unit 20 adjusts the second reference value to Av1 based on the first control signal ctr_Av; the output power adjustment unit 30 adjusts the third reference value to Vref1 based on the second control signal ctr_Vref; and the overvoltage protection threshold adjustment unit 40 adjusts the fourth reference value to OVP1 based on the third control signal ctr_OVP.

[0169] Reference Figure 7 A timing diagram of a charging process in an embodiment of this utility model is provided.

[0170] Figure 7 In the context of time t0~t1, the intelligent electronic device is in normal charging mode, with the second reference value being Av1, the third reference value being Vref1, and the fourth reference value being OVP1.

[0171] At time t1~t2, the control unit detects that the number of pulses is 2, determines that the target charging mode is fast charging mode 1, the second reference value is Av2, the third reference value is updated to Vref2, and the fourth reference value is OVP1.

[0172] At times t2 to t3, the control unit detects that the number of pulses is 3, determines that the target charging mode is fast charging mode 2, the second reference value is Av2, the third reference value is Vref2, and the fourth reference value is updated to OVP2.

[0173] At times t3 to t4, the control unit detects 4 pulses and determines the target charging mode as fast charging mode 3, the second reference value as Av2, the third reference value as Vref2, and the fourth reference value as OVP3.

[0174] At times t4 to t5, the control unit detects 5 pulses and determines the target charging mode as fast charging mode 4, with the second reference value being Av3, the third reference value being Vref3, and the fourth reference value being OVP4.

[0175] After time t5, the system enters reset mode, the second reference value is restored to Av1, the third reference value is restored to Vref1, and the fourth reference value is restored to OVP1.

[0176] In practical implementation, the signal detection unit 1011, counting unit 1012, control unit 1013, output parameter adjustment unit 1014, and drive control circuit 51 described above can be integrated into the same primary-side control chip. The switching transistor 52 described above can also be packaged in the primary-side control chip described above.

[0177] In specific implementations, the signal detection unit 1011, counting unit 1012, control unit 1013, output parameter adjustment unit 1014, and drive control circuit 51 mentioned above can be integrated into the same primary-side control chip, and the switching transistor 52 mentioned above can be packaged together with the primary-side control chip.

[0178] In practical implementation, the primary-side control circuit package structure includes a current sampling pin, a ground pin, a power supply pin, an output feedback pin, and a third terminal pin of the switching transistor; the first terminal of the switching transistor is connected to the drive control circuit, the second terminal of the switching transistor is connected to the sampling pin, and the third terminal of the switching transistor is connected to the third terminal pin of the switching transistor.

[0179] In practice, the current sampling pin, grounding pin, power supply pin, and output feedback pin are located on the first side of the primary-side control circuit's package structure, while the third pin of the switching transistor is located on the second side of the primary-side control circuit's package structure. The first and second sides are parallel.

[0180] In this embodiment of the invention, the primary-side control chip may include a sampling signal port, a power supply voltage port, and a feedback signal port. The sampling signal port is used to input a sampling signal; the power supply voltage port is used to input a power supply voltage; and the feedback signal port is used to input a feedback signal.

[0181] Combination Figure 1The primary-side control chip includes: sampling signal port CS, corresponding to pin ①; ground GND, corresponding to pin ②; power supply voltage port VCC, corresponding to pin ③; feedback signal port FB, corresponding to pin ④; unconnected port NC, corresponding to pin ⑤; and three output ports DRAIN, corresponding to pins ⑥, ⑦, and ⑧ respectively.

[0182] It should be noted that the primary-side control chip described above is merely an example and does not limit the primary-side control chip to include only the above eight pins, nor does it limit the specific function of each pin or the pin distribution order.

[0183] Reference Figure 6 A schematic diagram illustrating the connection relationship of an output parameter adjustment unit in the primary-side control chip according to an embodiment of this utility model is provided. It should be noted that... Figure 6 The control unit, counting unit, and signal detection unit are not shown in the figure; relevant descriptions can be found in the content provided in the above embodiments.

[0184] like Figure 6 As shown, the output terminal of the loop gain adjustment unit 20 is coupled to the second input terminal of the second comparator 21; the loop gain adjustment unit 20 is also coupled to pin ④ of the primary-side control chip to input a feedback signal; the first input terminal of the second comparator 21 is coupled to pin ① of the primary-side control chip to input a sampling signal; the output terminal of the second comparator 21 is coupled to the drive control circuit 51.

[0185] The output terminal of the output power adjustment unit 30 is coupled to the second input terminal of the third comparator 31; the first input terminal of the third comparator 31 is coupled to pin ① of the primary-side control chip; and the output terminal of the third comparator 31 is coupled to the drive control circuit 51.

[0186] The overvoltage protection threshold adjustment unit 40 is coupled to the second input terminal of the fourth comparator 41; the first input terminal of the fourth comparator 41 is coupled to pin ② of the primary-side control chip, and the input power supply voltage VCC is applied; the output terminal of the fourth comparator 41 is coupled to the drive control circuit 51.

[0187] The output of the drive control circuit 51 is coupled to the gate of the switching transistor 52. The drain of the switching transistor 52 is coupled to pin ① of the primary-side control chip, and the source of the switching transistor 52 is coupled to pins ⑥, ⑦, and ⑧ of the primary-side control chip.

[0188] In summary, in this embodiment of the present invention, the primary-side control circuit can reuse the feedback signal output by the optocoupler to determine the target charging mode and then adjust the output parameters without the need for an additional output voltage detection circuit. It is compatible with the existing primary-side control circuit packaging structure, thus reducing costs.

[0189] This utility model embodiment also provides a switching power supply, including the primary-side control circuit provided in any of the above embodiments, and the charging protocol interaction circuit provided in any of the above embodiments.

[0190] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A primary-side control circuit for a switching power supply, characterized in that, include: The signal detection unit receives a feedback signal and a first reference signal, compares the feedback signal and the first reference signal, and outputs a comparison signal. A counting unit, coupled to the output terminal of the signal detection unit, receives the comparison signal, counts the number of pulses of the comparison signal, and outputs a count value, wherein the count value represents the target charging mode. The control unit is connected to the output terminal of the counting unit and outputs a control signal according to the received count value; The output parameter adjustment unit receives the control signal and adjusts the output parameters corresponding to the target charging mode according to the control signal. The drive control circuit receives the output parameters and outputs a drive signal corresponding to the output parameters to the switching transistor.

2. The primary-side control circuit as described in claim 1, characterized in that, The count value is a first type of value, indicating that the target charging mode is a normal charging mode; the count value is a third type of value, indicating that the target charging mode has reverted to the normal charging mode; the count value is a second type of value, indicating that the target charging mode is a fast charging mode; the first type of value, the second type of value, and the third type of value are different and are positive integers.

3. The primary-side control circuit as described in claim 2, characterized in that, The output parameter adjustment unit is adapted to adjust at least one of the following output parameters: a second reference value corresponding to the loop gain, a third reference value corresponding to the output power, and a fourth reference value corresponding to the overvoltage protection.

4. The primary-side control circuit as described in claim 3, characterized in that, There are N types of fast charging modes, where N is a positive integer and N≥2.

5. The primary-side control circuit as described in claim 1, characterized in that, The signal detection unit includes a first comparator, a first input terminal of which receives the feedback signal, a second input terminal of which receives the first reference signal, and an output terminal of which is coupled to the counting unit.

6. The primary-side control circuit as described in claim 1, characterized in that, The output parameter adjustment unit includes a loop gain adjustment unit; the loop gain adjustment unit responds to K first control signals in the control signal and adjusts the second reference value corresponding to the loop gain according to the K first control signals.

7. The primary-side control circuit as described in claim 6, characterized in that, The loop gain adjustment unit includes: K switching units, L resistors connected in series to form a resistor string, and a second comparator. The first end of the resistor string is connected to an internal voltage source via a pull-up resistor, and the second end of the resistor string is grounded. The first input of the second comparator receives a sampled signal, and the second input of the second comparator is connected to a node between any two series resistors in the resistor string to receive the second reference value. The second comparator compares the sampled signal and the second reference value, and the output of the second comparator is connected to the drive control circuit. The i-th switch unit of the K switch units is connected in parallel across the j-th resistor in the resistor string. The control terminal of the i-th switch unit receives a corresponding first control signal provided by the control unit. When the first control signal corresponding to the i-th switch unit is valid, the i-th switch unit is turned on, short-circuiting the j-th resistor. Different switch units of the K switch units are connected in parallel across different resistors in the resistor string, thereby adjusting the second reference value. The drive control circuit drives the switching transistor; Where K, L, and i are all positive integers, and 1≤i≤K, 1≤j≤L, and L>K.

8. The primary-side control circuit as described in claim 1, characterized in that, The output parameter adjustment unit includes an output power adjustment unit; the output power adjustment unit responds to M second control signals in the control signal and adjusts the third reference value corresponding to the output power according to the M second control signals.

9. The primary-side control circuit as described in claim 8, characterized in that, The output power adjustment unit includes: M switching units and a third comparator, wherein: The first input terminal of the third comparator receives the sampled signal, the second input terminal of the third comparator receives the third reference signal, and the output terminal of the third comparator is connected to the drive control circuit. The first terminal of each of the M switching units receives a corresponding second control signal from the control unit. The second terminal of each of the M switching units is connected to the second input terminal of the third comparator. The third terminal of each of the M switching units receives M third reference values. The M switching units are controlled by receiving M second control signals. When the corresponding switching unit is turned on, the corresponding third reference value is used as the third reference signal of the third comparator. M is a positive integer.

10. The primary-side control circuit as described in claim 1, characterized in that, The output parameter adjustment unit includes an overvoltage protection threshold adjustment unit; the overvoltage protection threshold adjustment unit responds to N third control signals in the control signal and outputs a fourth reference value corresponding to overvoltage protection according to the N third control signals.

11. The primary-side control circuit as described in claim 10, characterized in that, The overvoltage protection threshold adjustment unit includes: N switching units and a fourth comparator, wherein: The first input terminal of the fourth comparator receives the power supply voltage, the second input terminal of the fourth comparator receives the fourth reference signal, and the output terminal of the fourth comparator is connected to the drive control circuit. The first terminal of each of the N switching units receives a corresponding third control signal from the control unit. The second terminal of each of the N switching units is connected to the second input terminal of the fourth comparator. The third terminal of each of the N switching units receives N fourth reference values. The N switching units are controlled by receiving N third control signals. When the corresponding switching unit is turned on, the corresponding fourth reference value is used as the fourth reference signal of the fourth comparator. N is a positive integer.

12. The primary-side control circuit as described in claim 2, characterized in that, Also includes: A zeroing unit is connected to the counting unit. When the count value is the third type of value, it outputs a zeroing signal to the counting unit.

13. The primary-side control circuit as described in claim 1, characterized in that, The drive signal output by the drive control circuit controls the switching transistor to turn on or off.

14. The primary-side control circuit as described in claim 13, characterized in that, The signal detection unit, the counting unit, the control unit, the output parameter adjustment unit, and the drive control circuit are integrated into the same primary-side control chip.

15. The primary-side control circuit as described in claim 14, characterized in that, The primary control chip and the switching transistor are packaged together.

16. The primary-side control circuit as described in claim 13, characterized in that, The signal detection unit, the counting unit, the control unit, the output parameter adjustment unit, the drive control circuit, and the switching transistor are integrated into the same chip.

17. The primary-side control circuit as described in claim 13, characterized in that, The primary-side control circuit's package structure includes a current sampling pin, a ground pin, a power supply pin, an output feedback pin, and a third terminal pin of the switching transistor; the first terminal of the switching transistor is connected to the drive control circuit, the second terminal of the switching transistor is connected to the sampling pin, and the third terminal of the switching transistor is connected to the third terminal pin of the switching transistor.

18. The primary-side control circuit as described in claim 13, characterized in that, The current sampling pin, ground pin, power supply pin, and output feedback pin are located on the first side of the package structure of the primary-side control circuit, and the third pin of the switching transistor is located on the second side of the package structure of the primary-side control circuit. The first side and the second side are parallel.

19. A switching power supply, characterized in that, include: Optical coupler, charging protocol interaction circuit, primary-side control circuit; The optocoupler is coupled to the charging protocol interaction circuit, and the 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 includes: The signal detection unit receives the feedback signal and the first reference signal, compares the feedback signal and the first reference signal, and outputs a comparison signal. A counting unit, coupled to the output terminal of the signal detection unit, receives the comparison signal, counts the number of pulses of the comparison signal, and outputs a count value, wherein the count value represents the target charging mode. The control unit is connected to the output terminal of the counting unit and outputs a control signal according to the received count value; The output parameter adjustment unit receives the control signal and adjusts the output parameters corresponding to the target charging mode according to the control signal. The drive control circuit receives the output parameters and outputs a drive signal corresponding to the output parameters to the switching transistor.

20. The switching power supply as described in claim 19, characterized in that, The count value is a first type of value, which indicates that the target charging mode is a normal charging mode; the count value is a third type of value, which indicates that the target charging mode has been restored to the normal charging mode; the number of pulses is a second type of value, which indicates that the target charging mode is a fast charging mode; the first type of value, the second type of value, and the third type of value are different and are positive integers.

21. The switching power supply as described in claim 20, characterized in that, The output parameter adjustment unit is adapted to adjust at least one of the following output parameters: a second reference value corresponding to the loop gain, a third reference value corresponding to the output power, and a fourth reference value corresponding to the overvoltage protection.

22. The switching power supply as described in claim 21, characterized in that, There are N types of fast charging modes, where N is a positive integer and N≥2.

23. The switching power supply as described in claim 19, characterized in that, The signal detection unit includes a first comparator, a first input terminal of which receives the feedback signal, a second input terminal of which receives the first reference signal, and an output terminal of which is coupled to the counting unit.

24. The switching power supply as described in claim 19, characterized in that, The output parameter adjustment unit includes a loop gain adjustment unit; the loop gain adjustment unit responds to K first control signals in the control signal and adjusts the second reference value corresponding to the loop gain according to the K first control signals.

25. The switching power supply as described in claim 24, characterized in that, The loop gain adjustment unit includes: K switching units, L resistors connected in series to form a resistor string, and a second comparator. The first end of the resistor string is connected to an internal voltage source via a pull-up resistor, and the second end of the resistor string is grounded. The first input of the second comparator receives a sampled signal, and the second input of the second comparator is connected to a node between any two series resistors in the resistor string to receive the second reference value. The second comparator compares the sampled signal and the second reference value, and the output of the second comparator is connected to the drive control circuit. The i-th switch unit of the K switch units is connected in parallel across the j-th resistor in the resistor string. The control terminal of the i-th switch unit receives a corresponding first control signal provided by the control unit. When the first control signal corresponding to the i-th switch unit is valid, the i-th switch unit is turned on, short-circuiting the j-th resistor. Different switch units of the K switch units are connected in parallel across different resistors in the resistor string, thereby adjusting the second reference value. The drive control circuit drives the switching transistor; Where K, L, and i are all positive integers, and 1≤i≤K, 1≤j≤L, and L>K.

26. The switching power supply as described in claim 19, characterized in that, The output parameter adjustment unit includes an output power adjustment unit; the output power adjustment unit responds to M second control signals in the control signal and adjusts the third reference value corresponding to the output power according to the M second control signals.

27. The switching power supply as described in claim 26, characterized in that, The output power adjustment unit includes: M switching units and a third comparator, wherein: The first input terminal of the third comparator receives the sampled signal, the second input terminal of the third comparator receives the third reference signal, and the output terminal of the third comparator is connected to the drive control circuit. The first terminal of each of the M switching units receives a corresponding second control signal from the control unit. The second terminal of each of the M switching units is connected to the second input terminal of the third comparator. The third terminal of each of the M switching units receives M third reference values. The M switching units are controlled by receiving M second control signals. When the corresponding switching unit is turned on, the corresponding third reference value is used as the third reference signal of the third comparator. M is a positive integer.

28. The switching power supply as described in claim 19, characterized in that, The output parameter adjustment unit includes an overvoltage protection threshold adjustment unit; the overvoltage protection threshold adjustment unit responds to N third control signals in the control signal and outputs a fourth reference value corresponding to the overvoltage protection according to the N third control signals.

29. The switching power supply as described in claim 28, characterized in that, The overvoltage protection threshold adjustment unit includes: N switching units and a fourth comparator, wherein: The first input terminal of the fourth comparator receives the power supply voltage, the second input terminal of the fourth comparator receives the fourth reference signal, and the output terminal of the fourth comparator is connected to the drive control circuit. The first terminal of each of the N switching units receives a corresponding third control signal from the control unit. The second terminal of each of the N switching units is connected to the second input terminal of the fourth comparator. The third terminal of each of the N switching units receives N fourth reference values. The N switching units are controlled by receiving N third control signals. When the corresponding switching unit is turned on, the corresponding fourth reference value is used as the fourth reference signal of the fourth comparator. N is a positive integer.

30. The switching power supply as described in claim 20, characterized in that, Also includes: A zeroing unit is connected to the counting unit. When the count value is the third type of value, it outputs a zeroing signal to the counting unit.

31. The switching power supply as described in claim 19, characterized in that, The drive signal output by the drive control circuit controls the switching transistor to turn on or off.

32. The switching power supply as described in claim 31, characterized in that, The signal detection unit, the counting unit, the control unit, the output parameter adjustment unit, and the drive control circuit are integrated into the same primary-side control chip.

33. The switching power supply as described in claim 32, characterized in that, The primary control chip and the switching transistor are packaged together.

34. The switching power supply as described in claim 31, characterized in that, The signal detection unit, the counting unit, the control unit, the output parameter adjustment unit, the drive control circuit, and the switching transistor are integrated into the same chip.

35. The switching power supply as described in claim 33, characterized in that, The primary-side control circuit's package structure includes a current sampling pin, a ground pin, a power supply pin, an output feedback pin, and a third terminal pin of the switching transistor. The first terminal of the switching transistor is connected to the drive control circuit, the second terminal of the switching transistor is connected to the sampling pin, and the third terminal of the switching transistor is connected to the third terminal pin of the switching transistor.

36. The switching power supply as described in claim 35, characterized in that, The current sampling pin, ground pin, power supply pin, and output feedback pin are located on the first side of the primary-side control circuit's package structure, and the third terminal pin of the switch is located on the second side of the primary-side control circuit's package structure. The first and second sides are parallel.

37. The switching power supply as described in claim 19, characterized in that, The first end of the optocoupler is coupled to the charging protocol interaction circuit, the second end of the optocoupler is coupled to the output end of the switching power supply, the third end of the optocoupler is coupled to the primary-side control circuit, and the fourth end of the optocoupler is grounded; the output signal of the charging protocol interaction circuit is transmitted to the receiving end of the feedback signal of the primary-side control circuit through the optocoupler, and the fourth end of the optocoupler is connected to the current sampling pin of the primary-side control circuit through a resistor.

38. The switching power supply as described in claim 37, characterized in that, The charging protocol interaction circuit includes: a charging protocol interaction unit and a switching unit, wherein: The charging protocol interaction unit is coupled to the charging interface circuit and, in response to the identified target charging mode, outputs a fourth control signal to the control terminal of the switching unit. The switching unit has a first terminal coupled to the first terminal of an optocoupler and a second terminal grounded; the fourth control signal controls the number of times the switching unit is turned on, and the number of times the switching unit is turned on is related to the target charging mode.

39. The switching power supply as described in claim 38, characterized in that, The charging interface circuit interacts with the smart electronic device via a charging protocol to determine whether the switching power supply supports the fast charging mode of the smart electronic device.

40. The switching power supply as described in claim 39, characterized in that, The charging protocol interaction unit is connected between the output voltage of the switching power supply and ground.

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