A constant power charger control circuit

Abstract

The application relates to a constant-power charger control circuit, which comprises a DA module, a first voltage comparison module, a second voltage comparison module, a digital logic operation module, a control module and an adjusting module. The first voltage comparison module and the second voltage comparison module both compare the feedback voltage at the end of an auxiliary winding of a transformer with the reference voltage output by the DA module, and output a first voltage comparison result and a second voltage comparison result respectively; the digital logic operation module updates the reference voltage value and the adjusting current value after logical processing according to the first voltage comparison result; the DA module converts the reference voltage value and the adjusting current value into analog signals; the control module receives the second voltage comparison result and the adjusting current value, controls the adjusting module, realizes the adjustment of the output voltage V OUT of the charger, and guarantees the normal charging of intelligent devices. The above technical scheme can adjust the output voltage of the charger according to the demand of the intelligent device, and avoids the problem that the intelligent device cannot be normally charged.

Description

Technical Field

[0001] This application relates to the field of circuit design technology, and in particular to a constant power charger control circuit. Background Technology

[0002] With the development of fast charging technology, some fast charging protocols, such as PD and QC3.0+, now have power indication functions. Smart devices using these charging protocols (such as mobile phones, tablets, Bluetooth devices, etc.) can communicate with the charger, allowing the charger to adjust and adapt according to the charging power of the smart device, thereby enabling fast charging.

[0003] However, some smart devices using QC2.0, QC3.0, or MTK protocols lack power indication functionality. If the charger used by these users can provide less current than the smart device requires, the charger will self-protect when connected to the smart device. The charger will reduce its output voltage to 0V and disconnect charging from the smart device. Simultaneously, the charger will switch to its initial state and wait for the next connection attempt. At this point, the smart device will try to reconnect to the charger, and the charger will again self-protect and disconnect charging from the smart device. This cycle repeats, causing the smart device to constantly turn its screen on and off, preventing normal charging and resulting in a poor user experience during charging. Summary of the Invention

[0004] To address the issue of smart devices failing to charge properly and experiencing a poor user experience during charging due to incompatibility between the charger and the device lacking power indication functionality, this application provides a constant power charger control circuit.

[0005] This application provides a constant power charger control circuit, which adopts the following technical solution:

[0006] A constant power charger control circuit, wherein the control circuit is connected to the primary winding and auxiliary winding of a transformer, and the feedback voltage V at the auxiliary winding terminal of the transformer is... FB Used to reflect the output voltage V at the secondary winding terminal of the transformer OUT The magnitude of the output voltage V is achieved through the control circuit. OUT Regulation;

[0007] The control circuit includes: a DA module, a first voltage comparison module, a second voltage comparison module, a digital logic operation module, a control module, and an adjustment module;

[0008] The DA module is used to receive the regulating current I output by the digital logic operation module. reg Value and reference voltage V REFThe value of the regulating current I reg Value and reference voltage V REF The value is converted into an analog signal, and the converted regulating current I is... reg The value is output to the control module, and the converted reference voltage V REF The value is output to the first voltage comparison module and the second voltage comparison module;

[0009] The first voltage comparison module is used to receive the reference voltage V REF Value and the feedback voltage V FB The value is compared with the reference voltage V. REF Value and the feedback voltage V FB The value is used to generate a first voltage comparison result, and the first voltage comparison result is output to the digital logic operation module;

[0010] The second voltage comparison module is used to receive the reference voltage V REF Value and the feedback voltage V FB The value is compared with the reference voltage V. REF Value and the feedback voltage V FB The value is used to generate a second voltage comparison result, and the second voltage comparison result is output to the control module;

[0011] The digital logic operation module determines whether the CC_CV_MODE signal is high or low based on the first voltage comparison result, confirms entry into CV mode or CC mode based on the CC_CV_MODE signal, and updates the regulating current I based on the CV mode or CC mode. reg Value and reference voltage V REF The value is then output to the DA module;

[0012] The control module is used to adjust the current I received. reg The switching frequency value C is generated by comparing the value with the second voltage. f and pulse width value C p The control signal is sent to the regulating module.

[0013] The adjustment module is used to adjust the output voltage V according to the received control signal. OUT .

[0014] By adopting the above technical solution, a control circuit is added to the auxiliary winding of the transformer, enabling timely feedback on the voltage and current status of the smart device. The control circuit also enables precise adjustment of the charger's output voltage and current, thereby improving the charger's performance.

[0015] In one specific implementation, the digital logic operation module samples the first voltage comparison result according to a preset interval time t1.

[0016] By adopting the above technical solution, the digital logic operation module presets the sampling time interval for the first voltage comparison result output by the first voltage comparison module, ensuring the adjustment effect of the charger's output voltage and output current, and improving the working efficiency of the control circuit.

[0017] In one specific implementation scheme, the digital logic operation module is pre-set with a maximum voltage V. MAX Maximum current I MAX Reference voltage V REF and regulating current I reg The CV mode processing procedure includes: the digital logic operation module comparing the reference voltage V REF Value and maximum voltage V MAX Value, if the reference voltage V REF The value is greater than or equal to the maximum voltage V. MAX If the value is specified, the digital logic operation module will calculate the maximum voltage V. MAX The value is updated to the reference voltage V. REF Value, while also setting the maximum current I MAX The value is updated to the regulating current I. reg value.

[0018] By adopting the above technical solution, and by presetting multiple parameters in the digital logic operation module, the corresponding adjustment mode is entered according to the situation of the smart device, making the operation logic clearer. In CV mode, when the reference voltage value is greater than or equal to the maximum voltage value, the digital logic operation module updates the maximum voltage value and the maximum current value to ensure that the control circuit correctly judges and processes the voltage and current required by the smart device.

[0019] In one specific implementation, the CV mode processing includes: the digital logic operation module comparing the reference voltage V... REF Value and maximum voltage V MAX Value, if the reference voltage V REF The value is less than the maximum voltage V MAX If the value is specified, the digital logic operation module will adjust the current I. reg The value gradually decreases according to the preset step size ΔI, while the reference voltage V is increased accordingly while ensuring constant power. REF value.

[0020] By adopting the above technical solution, in CV mode, when the reference voltage value is less than the maximum voltage value, the digital logic operation module will gradually reduce the adjustment current according to the preset step size, and finally increase the charger output voltage and reduce the charger output current to improve the charging efficiency of smart devices.

[0021] In one specific implementation scheme, the CC mode processing includes: the digital logic operation module comparing the regulating current I... reg Value and maximum current I MAX Value, if the regulating current I reg The value is greater than or equal to the maximum current I. MAX If the value is specified, the digital logic operation module will calculate the maximum current I. MAX The value is updated to the regulating current I. reg Value, and simultaneously the maximum voltage V MAX The value is updated to the reference voltage V. REF value.

[0022] By adopting the above technical solution, in CC mode, when the adjusted current value is greater than or equal to the maximum current value, the digital logic operation module updates the maximum current value and the maximum voltage value to ensure that the control circuit correctly judges and processes the voltage and current required by the intelligent device.

[0023] In one specific implementation scheme, the CC mode processing includes: the digital logic operation module comparing the regulating current I... reg Value and maximum current I MAX Value, if the regulating current I reg The value is less than the maximum current I MAX If the value is specified, the digital logic operation module will adjust the current I. reg The value gradually increases according to the preset step size ΔI, while the reference voltage V decreases accordingly while ensuring constant power. REF value.

[0024] By adopting the above technical solution, in CC mode, when the adjusted current value is less than the maximum current value, the digital logic operation module will gradually increase the adjusted current according to the preset step size, and finally reduce the charger output voltage and increase the charger output current, so as to avoid the output voltage of the transformer secondary winding terminal dropping to 0V and causing the problem of not being able to charge.

[0025] In one specific implementation, the reference voltage V REF Adjusting current I reg Maximum current I MAX and maximum voltage V MAX Configurable settings.

[0026] By adopting the above technical solution, various parameters in the program control module can be set according to the charger specifications, thereby improving the practicality of the charger.

[0027] In one specific implementation, the adjustment module includes a MOS transistor, the gate of which is connected to the output terminal of the control module, the drain of which is connected to the primary winding of the transformer, and the source of which is grounded through a series resistor.

[0028] By adopting the above technical solution, the MOSFET has better switching control function. The control module regulates the charger's output voltage by controlling the MOSFET, and the regulation process is faster.

[0029] In summary, the technical solution of this application includes at least the following beneficial technical effects:

[0030] 1. By adopting a constant power control method, the charger's output voltage and current can be adjusted according to the voltage and current required by the smart device. This avoids the problem of the charger's output voltage dropping directly to 0V when the smart device's required current is greater than the current provided by the charger, which would prevent the smart device from charging normally and result in a poor user experience during the charging process. This improves the charger's practicality. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the control circuit structure of a specific embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the circuit structure of the control circuit according to a specific embodiment of this application;

[0033] Figure 3 This is a schematic diagram of the processing logic of the digital logic operation module in a specific embodiment of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. DA module; 2. First voltage comparison module; 21. First comparator; 3. Second voltage comparison module; 31. Second comparator; 4. Digital logic operation module; 5. Control module; 51. PSR PWM PFM controller; 6. Adjustment module. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0037] This application discloses a constant power charger control circuit, which is connected to both the primary winding and the auxiliary winding of transformer T. Figure 1 and Figure 2 As shown, ports 1 and 2 are the primary windings of transformer T, ports 3 and 4 are the auxiliary windings of transformer T, and ports 5 and 6 are the secondary windings of transformer T. The feedback voltage V at the auxiliary winding terminals of transformer T is... FB The magnitude is related to the output voltage V at the secondary winding terminal of transformer T. OUT The magnitude is directly proportional to the value of the feedback voltage V at the auxiliary winding terminal of transformer T. FB The magnitude can reflect the output voltage V at the secondary winding terminal of transformer T. OUT The magnitude of the voltage can be controlled by the control circuit to change the voltage at the primary winding of transformer T, thereby achieving the output voltage V at the secondary winding of transformer T. OUT and output current I OUT The adjustment.

[0038] Reference Figure 2 The control circuit includes a DA module 1, a first voltage comparison module 2, a second voltage comparison module 3, a digital logic operation module 4, a control module 5, and an adjustment module 6. The first voltage comparison module 2 includes a first comparator 21, the second voltage comparison module 3 includes a second comparator 31, the control module 5 includes a PSR PWM PFM controller 51, and the adjustment module 6 includes a MOSFET Q1.

[0039] Reference Figure 2 The gate of MOSFET Q1 is connected to the output terminal of PSR PWM PFM controller 51. The drain of MOSFET Q1 is connected to the positive terminal of diode D1. The source of MOSFET Q1 is connected to ground in series with resistor R1. Capacitors C1 and C2 are connected in series and then in parallel with resistor R4. Resistors R5 and R6 are connected in parallel, one end of which is connected to the negative terminal of diode D1, and the other end is connected to the loop formed by capacitors C1, C2, and R4. The other end of the loop formed by capacitors C1, C2, and R4 is connected to port 1 of the primary winding of transformer T. Port 2 of the primary winding of transformer T is connected to the drain of MOSFET Q1. Port 3 of the auxiliary winding of transformer T is connected to ground in series with resistors R3 and R2. Port 4 of the auxiliary winding of transformer T is grounded.

[0040] Specifically, the non-inverting inputs of the first comparator 21 and the second comparator 31 are both connected to port 3 of the auxiliary winding of transformer T through resistor R3. The inverting inputs of the first comparator 21 and the second comparator 31 are both connected to the output of DA module 1. The output of the first comparator 21 is connected to the input of digital logic operation module 4. The output of the second comparator 31 is connected to the input of PSR PWM PFM controller 51. The output of digital logic operation module 4 is connected to the input of DA module 1. The output of DA module 1 is connected to the input of PSR PWM PFM controller 51, the inverting input of the first comparator 21, and the inverting input of the second comparator 31, respectively.

[0041] DA module 1 is used to receive the regulating current I output from digital logic operation module 4. reg Value and reference voltage V REF Value, and will adjust the current I reg Value and reference voltage V REF The value is converted into an analog signal, and the converted regulating current I is... reg The value is output to control module 5, which converts the reference voltage V. REF The value is output to the first voltage comparison module 2 and the second voltage comparison module 3.

[0042] The first voltage comparator module 2 is used to receive the reference voltage V output by the DA module 1. REF The value and the feedback voltage V at the auxiliary winding terminal of transformer T FB The value is compared with the reference voltage V. REF Value and feedback voltage V FB The value is used to generate the first voltage comparison result, and the first voltage comparison result is output to the digital logic operation module 4.

[0043] The second voltage comparison module 3 is used to receive the reference voltage V output by the DA module 1. REF The value and the feedback voltage V at the auxiliary winding terminal of transformer T FB The value is compared with the reference voltage V. REF Value and feedback voltage V FB The value is used to generate a second voltage comparison result, which is then output to control module 5 to ensure the feedback voltage V at the auxiliary winding terminal of transformer T. FB The sampling is constant, thus ensuring the output voltage V at the secondary winding terminal of transformer T. OUT Constant.

[0044] The digital logic operation module 4 determines whether the CC_CV_MODE signal is high or low based on the first voltage comparison result, and confirms whether to enter CV mode or CC mode based on the CC_CV_MODE signal. After logic processing in CV mode or CC mode, it updates the regulating current I. regValue and reference voltage V REF The value is then output to DA module 1.

[0045] Control module 5 adjusts the received current I reg The switching frequency value C is generated by comparing the value with the second voltage. f and pulse width value C p The control signal is sent and output to the adjustment module 6.

[0046] The adjustment module 6 is used to adjust the output voltage V according to the received control signal. OUT .

[0047] The digital logic operation module 4 samples the first voltage comparison result output by the first voltage comparison module 2 according to the preset interval time t1.

[0048] Digital logic operation module 4 is pre-set with a reference voltage V REF Adjusting current I reg Maximum voltage V MAX Maximum current I MAX and regulating current I reg The stride ΔI.

[0049] Digital logic operation module 4, the CV mode processing procedure includes: the digital logic operation module compares the reference voltage V. REF Value and maximum voltage V MAX value:

[0050] If the reference voltage V REF The value is greater than or equal to the maximum voltage V MAX If the value is , then the digital logic operation module 4 will set the maximum voltage V. MAX The value is updated to the reference voltage V. REF Value, while also setting the maximum current I MAX The value is updated to the regulating current I. reg value;

[0051] If the reference voltage V REF The value is less than the maximum voltage V MAX If the value is specified, then the digital logic operation module 4 will adjust the current I. reg The value gradually decreases according to the preset step size ΔI, while the reference voltage V is increased accordingly while ensuring constant power. REF value.

[0052] The processing procedure of digital logic operation module 4 in CC mode is as follows: Digital logic operation module 4 compares and adjusts the current I. reg With the maximum current I MAX value:

[0053] If the current I is adjusted regThe value is greater than or equal to the maximum current I. MAX If the value is specified, then the digital logic operation module 4 will set the maximum current I. MAX The value is updated to the regulating current I. reg Value, and simultaneously the maximum voltage V MAX The value is updated to the reference voltage V. REF value;

[0054] If the current I is adjusted reg The value is less than the maximum current I MAX If the value is specified, then the digital logic operation module 4 will adjust the current I. reg The value gradually increases according to the preset step size ΔI, while the reference voltage V decreases accordingly while ensuring constant power. REF value.

[0055] Preferably, the preset interval t1 for the digital logic operation module 4 to sample the first voltage comparison result output by the first voltage comparison module 2 is 160us.

[0056] Scenario 1: Initially, a reference voltage V is preset. REF 9V, adjust current I reg It is 2A, and the maximum voltage is V. MAX 9V, maximum current I MAX The digital logic operation module 4 samples the first voltage comparison result output by the first voltage comparison module 2 at a preset interval t1 of 160us. The digital logic operation module 4 then adjusts the current I... reg The step size ΔI is 50mA when the value gradually increases or decreases.

[0057] S10: When the charger and smart device are connected, and the charging current of the smart device is greater than 2A, that is, when the charging current of the smart device is greater than the regulated current I... reg The output voltage V at the secondary winding terminal of transformer T OUT The voltage will drop due to the feedback effect of the transformer's auxiliary winding. At this time, the feedback voltage V at the auxiliary winding terminal of transformer T will be low. FB The correspondingly smaller value is V. FB The value will be lower than 9V. The voltage comparison results of the first comparator 21 and the second comparator 31 are both low level, and the digital logic operation module 4 enters CC mode.

[0058] S20: Digital logic operation module 4 compares and adjusts current I reg With the maximum current I MAX The magnitude of the current I is then adjusted. reg The current is 2A, and the maximum current I is... MAX It is 3A, that is, the regulating current I reg Less than the maximum current I MAXIf the value is specified, then the digital logic operation module 4 will adjust the current I according to the preset step size of 50mA. reg Gradually increase the A from 2A to 3A, while maintaining a constant power of 18W, and adjust the reference voltage V. REF The value gradually decreases from 9V to 6V.

[0059] S30: DA module 1 will adjust the reference voltage V after digital logic operation module 4. REF The value is converted into an analog signal and output to the inverting input of the first comparator 21 and the second comparator 31 for the next comparison; the DA module 1 converts the adjusted current I from the digital logic operation module 4 into an analog signal. reg The value is converted into an analog signal and output to the PSR PWM PFM controller 51. The PSR PWM PFM controller 51 receives the regulating current I output from the DA module 1. reg The low-level signal output by the second comparator 31 controls the switching frequency and pulse width of the MOSFET Q1, thereby controlling the output voltage V at the secondary winding of the transformer T. OUT Gradually decrease, output current I OUT Gradually increase the voltage to avoid increasing the output voltage V at the secondary winding terminal of transformer T. OUT It dropped directly to 0V.

[0060] S40: As the smart device is charged, the battery voltage of the smart device increases, and the output voltage V of the secondary winding of transformer T increases. OUT The feedback voltage V at the auxiliary winding terminal of transformer T is relatively large. FB The corresponding increase is higher than the reference voltage V at this time. REF The value is 9V. The voltage comparison results of the first comparator 21 and the second comparator 31 are both high level, and the digital logic operation module 4 enters CV mode.

[0061] S50: Digital Logic Operation Module 4 compares reference voltage V REF With the maximum voltage V MAX The magnitude of the reference voltage V at this time REF It is 6V, and the maximum voltage is V. MAX It is 9V, which is the reference voltage V. REF Less than the maximum voltage V MAX If the value is specified, then the digital logic operation module 4 will adjust the current I according to the preset step size of 50mA. reg Gradually reduce the A from 3A to 2A while maintaining a constant power of 18W, and adjust the reference voltage V. REF The value gradually increases from 6V to 9V.

[0062] S60: DA module 1 adjusts the reference voltage V after digital logic operation module 4.REF The value is converted into an analog signal and output to the inverting input of the first comparator 21 and the second comparator 31 for the next comparison; the DA module 1 converts the adjusted current I from the digital logic operation module 4 into an analog signal. reg The value is converted into an analog signal and output to the PSR PWM PFM controller 51. The PSR PWM PFM controller 51 receives the regulating current I output from the DA module 1. reg The high-level signal output by the second comparator 31 controls the switching frequency and pulse width of the MOSFET Q1, thereby controlling the output voltage V at the secondary winding of the transformer T. OUT Gradually increase the output current I OUT Gradually reduce the speed to ensure normal charging of smart devices.

[0063] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A constant power charger control circuit, characterized in that, The control circuit is connected to the primary winding and auxiliary winding of the transformer, and the feedback voltage V at the auxiliary winding terminal of the transformer is... FB Used to reflect the output voltage V at the secondary winding terminal of the transformer OUT The magnitude of the output voltage V is achieved through the control circuit. OUT Regulation; The control circuit includes: a DA module (1), a first voltage comparison module (2), a second voltage comparison module (3), a digital logic operation module (4), a control module (5), and an adjustment module (6); The DA module (1) is used to receive the regulating current I output by the digital logic operation module (4). reg Value and reference voltage V REF The value of the regulating current I reg Value and reference voltage V REF The value is converted into an analog signal, and the converted regulating current I is... reg The value is output to the control module (5), and the converted reference voltage V is converted to a reference voltage V. REF The value is output to the first voltage comparison module (2) and the second voltage comparison module (3); The first voltage comparison module (2) is used to receive the reference voltage V. REF Value and the feedback voltage V FB The value is compared with the reference voltage V. REF Value and the feedback voltage V FB The value is used to generate a first voltage comparison result, and the first voltage comparison result is output to the digital logic operation module (4); The second voltage comparison module (3) is used to receive the reference voltage V. REF Value and the feedback voltage V FB The value is compared with the reference voltage V. REF Value and the feedback voltage V FB The value is used to generate a second voltage comparison result, and the second voltage comparison result is output to the control module (5); The digital logic operation module (4) determines whether the CC_CV_MODE signal is high or low based on the first voltage comparison result, confirms entry into CV mode or CC mode based on the CC_CV_MODE signal, and updates the regulating current I based on the CV mode or CC mode. reg Value and reference voltage V REF The value is then output to the DA module (1); The control module (5) is used to adjust the current I received according to the received current. reg The switching frequency value C is generated by comparing the value with the second voltage. f and pulse width value C p The control signal is sent to the regulating module (6); The adjustment module (6) is used to adjust the output voltage V according to the received control signal. OUT .

2. The constant power charger control circuit according to claim 1, characterized in that: The digital logic operation module (4) samples the first voltage comparison result according to the preset interval time t1.

3. The constant power charger control circuit according to claim 1, characterized in that: The digital logic operation module (4) is pre-set with a maximum voltage V. MAX Maximum current I MAX Reference voltage V REF and regulating current I reg The CV mode processing includes: the digital logic operation module (4) comparing the reference voltage V REF Value and maximum voltage V MAX Value, if the reference voltage V REF The value is greater than or equal to the maximum voltage V. MAX If the value is specified, then the digital logic operation module (4) will calculate the maximum voltage V. MAX The value is updated to the reference voltage V. REF Value, while also setting the maximum current I MAX The value is updated to the regulating current I. reg value.

4. The constant power charger control circuit according to claim 3, characterized in that: The CV mode processing includes: the digital logic operation module (4) comparing the reference voltage V REF Value and maximum voltage V MAX Value, if the reference voltage V REF The value is less than the maximum voltage V MAX If the value is specified, then the digital logic operation module (4) will adjust the current I. reg The value gradually decreases according to the preset step size ΔI, while the reference voltage V is increased accordingly while ensuring constant power. REF value.

5. A constant power charger control circuit according to claim 3, characterized in that: The CC mode processing includes: the digital logic operation module (4) comparing the regulating current I reg Value and maximum current I MAX Value, if the regulating current I reg The value is greater than or equal to the maximum current I. MAX If the value is specified, then the digital logic operation module (4) will calculate the maximum current I. MAX The value is updated to the regulating current I. reg Value, and simultaneously the maximum voltage V MAX The value is updated to the reference voltage V. REF value.

6. The constant power charger control circuit according to claim 3, characterized in that: The CC mode processing includes: the digital logic operation module (4) comparing the regulating current I reg Value and maximum current I MAX Value, if the regulating current I reg The value is less than the maximum current I MAX If the value is specified, then the digital logic operation module (4) will adjust the current I. reg The value gradually increases according to the preset step size ΔI, while the reference voltage V decreases accordingly while ensuring constant power. REF value.

7. A constant power charger control circuit according to any one of claims 3 to 6, characterized in that: The reference voltage V REF Adjusting current I reg Maximum current I MAX and maximum voltage V MAX Configurable settings.

8. The constant power charger control circuit according to claim 1, characterized in that: The adjustment module includes a MOS transistor, the gate of which is connected to the output terminal of the control module (5), the drain of which is connected to the primary winding of the transformer, and the source of which is grounded through a series resistor.

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