Charging voltage follower circuit based on PWM (Pulse Width Modulation) and electric equipment

Abstract

The embodiment of the utility model relates to the technical field of charging, in particular to a PWM-based charging voltage follower circuit and electric equipment. According to the embodiment of the utility model, the switching circuit is arranged, and the PWM signal is output to the switching circuit according to the monitored voltage input value so as to dynamically adjust the adjusting circuit. The effect of adaptively following the output voltage of the charger is realized, and the charger can continuously and stably output constant voltage; and the circuit is simple, the production cost can be greatly reduced through the circuit scheme, and the circuit can be widely applied to industrial production.

Description

Technical Field

[0001] The embodiments of the utility model relate to the field of charging technology, and in particular to a PWM-based charging voltage follower circuit and an electrical device. Background Art

[0002] To prevent the buck-boost modulation IC from being out of regulation when working in charging mode, generating a load current that exceeds the output current capacity of the charger, causing the charger output to be overloaded and affecting normal charging, the circuit outside the modulation IC needs to dynamically set a reference voltage based on the current output voltage of the charger. The reference voltage is proportional to the current minimum output voltage limit of the charger. When the modulation IC detects that the reference voltage is less than or equal to the minimum output voltage limit of the current gear of the charger, it can reduce the input current of the charger in time to ensure that the charger can output at a normal constant voltage.

[0003] Currently, modulation ICs are used to achieve adaptive following of charger output voltage, usually using operational amplifiers or control chips with DA functions for modulation. The circuits of the above modulation methods are complex and expensive, and are not suitable for large-scale industrial production. Utility Model Content

[0004] In view of the above problems, the embodiments of the present utility model provide a charging voltage follower circuit and an electrical device based on PWM, which solves the problem that the circuit is complex and expensive when modulating through an operational amplifier.

[0005] First,

[0006] The utility model provides a charging voltage following circuit based on PWM, the circuit comprising:

[0007] A monitoring circuit is connected to a charging input terminal of the charger to monitor a voltage input value of the charger;

[0008] A regulating circuit connected to the charging input terminal to adjust the voltage value of the reference voltage terminal of the reference circuit;

[0009] A reference circuit is connected to the regulating circuit and outputs a reference voltage value to the regulating circuit;

[0010] A switch circuit connected to the regulating circuit to modulate the change of the impedance of the regulating circuit to ground;

[0011] And a main control chip is provided with a signal input terminal and a control output terminal, the signal input terminal is connected to the monitoring circuit, the control output terminal is connected to the switching circuit, and according to the monitored voltage input value, a PWM signal is output to the switching circuit to dynamically adjust the regulation circuit.

[0012] In some optional embodiments, the regulating circuit is provided with a voltage regulating end, and the regulating circuit further comprises a first resistor, a second resistor, and a third resistor, and the first resistor, the second resistor, and the third resistor are respectively connected in parallel to the voltage regulating end;

[0013] The other end of the first resistor is connected to the charging input terminal, the other end of the second resistor is connected to the switch circuit, and the other end of the third resistor is grounded;

[0014] The voltage regulating terminal is also connected to the reference circuit.

[0015] In some optional embodiments, the reference circuit includes a buck-boost modulation management chip and an RC filter circuit. The buck-boost modulation management chip is provided with a reference voltage terminal, and the reference voltage terminal is connected to the voltage regulation terminal through the RC filter circuit.

[0016] In some optional embodiments, the RC filter circuit includes a fourth resistor and a first capacitor, one end of the fourth resistor is connected to the reference voltage terminal and the other end is connected to the voltage regulation terminal; one end of the first capacitor is connected to the reference voltage terminal and the other end is grounded.

[0017] In some optional embodiments, the switch circuit includes a MOS tube, a gate of the MOS tube is connected to the control output terminal, a drain is connected to the switch circuit, and a source is grounded.

[0018] In some optional embodiments, a fifth resistor is further connected between the gate of the MOS tube and the control output terminal.

[0019] In some optional embodiments, the switch circuit further includes a sixth resistor, one end of the sixth resistor is connected to the gate of the MOS tube, and the other end of the sixth resistor is connected to the power ground.

[0020] In some optional embodiments, the monitoring circuit includes a monitoring chip, and the monitoring chip includes a monitoring input terminal and a monitoring output terminal, the monitoring input terminal is connected to the charging input terminal of the charger, and the monitoring output terminal is connected to the signal input terminal.

[0021] In some optional embodiments, the charger is a charger that supports the PD protocol, the QC protocol, or the SCP protocol, and the voltage input value of the charger is any value between 5V and 28V.

[0022] Second,

[0023] The utility model provides an electric device, comprising a shell and a circuit board arranged inside the shell, wherein the circuit board is integrated with the above-mentioned PWM-based charging voltage follower circuit.

[0024] The embodiment of the utility model sets a switch circuit and outputs a PWM signal to the switch circuit according to the monitored voltage input value to dynamically adjust the regulation circuit. The effect of adaptively following the output voltage of the charger is achieved to ensure that the charger can continuously and stably output at a constant voltage. The circuit is simple, and the production cost can be greatly reduced through this circuit solution, which can be applied to a wide range of industrial production.

[0025] The above description is only an overview of the technical solution of the embodiment of the utility model. In order to more clearly understand the technical means of the embodiment of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are only used to illustrate the embodiments and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. In the accompanying drawings:

[0027] Figure 1 The schematic diagram of the structure of the PWM-based charging voltage follower circuit provided by the utility model is shown;

[0028] Figure 2 The circuit schematic diagram of the PWM-based charging voltage follower circuit provided by the utility model is shown;

[0029] Figure 3 The utility model shows a schematic structural diagram of the electric equipment provided by the utility model.

[0030] in,

[0031] 110, monitoring circuit; 120, regulating circuit; 140, reference circuit; 130, switching circuit; U1, main control chip; U2, buck-boost modulation management chip; U3, monitoring chip; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; C1, first capacitor; Q1, first MOS tube; 310, electrical equipment; 320, circuit board. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein.

[0033] Embodiment 1:

[0034] Figure 1The utility model shows a first embodiment of a PWM-based charging voltage follower circuit, the circuit includes a monitoring circuit 110, a regulating circuit 120, a reference circuit 140, a switch circuit 130, and a main control chip U1. Among them, the monitoring circuit 110 is connected to the charging input terminal of the charger to monitor the voltage input value of the charger; the regulating circuit 120 is connected to the charging input terminal to adjust the voltage value of the reference voltage terminal of the reference circuit; the reference circuit 140 is connected to the regulating circuit 120 and outputs a reference voltage value to the regulating circuit 120; the switch circuit 130 is connected to the regulating circuit 120 to modulate the change of the impedance of the regulating circuit 120 to the ground; the main control chip U1 is provided with a signal input terminal U1_COM and a control output terminal U1_PWM, the signal input terminal U1_COM is connected to the monitoring circuit 110, the control output terminal U1_PWM is connected to the switch circuit 130, and according to the monitored voltage input value, a PWM signal is output to the switch circuit 130 to dynamically adjust the regulating circuit 120.

[0035] In this embodiment, the voltage modulation is performed by replacing the operational amplifier with the switch circuit 130. And the scheme of this application is more stable and economical. The embodiment of the utility model sets the switch circuit 130, and outputs a PWM signal to the switch circuit 130 according to the monitored voltage input value to dynamically adjust the adjustment circuit 120. The effect of adaptively following the output voltage of the charger is achieved, ensuring that the charger can continuously and stably output at a constant voltage; and the circuit is simple. The production cost can be greatly reduced through this circuit scheme, and it can be applied to a wide range of industrial production.

[0036] Embodiment 2:

[0037] Figure 2 The utility model shows a second embodiment of a PWM-based charging voltage follower circuit. Based on embodiment 1, this embodiment provides a specific implementation method on the basis of embodiment 1. The utility model embodiment sets a switch circuit and outputs a PWM signal to the switch circuit according to the monitored voltage input value to dynamically adjust the regulation circuit. The dynamic modulation of the charging start voltage input value is realized to enable the adaptive following of the charger output voltage; and the circuit is simple. The production cost can be greatly reduced through this circuit solution, and it can be applied to a wide range of industrial production. Specifically including:

[0038] The adjustment circuit 120 is provided with a voltage adjustment terminal A, and the adjustment circuit 120 further includes a first resistor R1, a second resistor R2, and a third resistor R3. The first resistor R1, the second resistor R2, and the third resistor R3 are respectively connected in parallel to the voltage adjustment terminal A; the other end of the first resistor R1 is connected to the charging input terminal, the other end of the second resistor R2 is connected to the switch circuit 130, and the other end of the third resistor R3 is grounded; the voltage adjustment terminal A is also connected to the reference circuit 140. In this embodiment, the adjustment circuit 120 is provided with a voltage adjustment terminal A, and this solution takes this point as the modulation point of voltage modulation. The connection between the voltage adjustment terminal A and the switch circuit 130 can control the change of the impedance of the first resistor R1, the second resistor R2, and the third resistor R3 to the ground through the switch circuit 130, so as to realize the dynamic adjustment of the voltage of the voltage adjustment terminal A. In addition, the voltage adjustment terminal A is also connected to the reference circuit 140, which is used to reduce the input current to maintain the input voltage of the charger at a set value.

[0039] The reference circuit 140 includes a buck-boost modulation management chip U2 and an RC filter circuit. The buck-boost modulation management chip U2 is provided with a reference voltage terminal U2_Verf, and the reference voltage terminal U2_Verf is connected to the voltage adjustment terminal A through the RC filter circuit. In this embodiment, the reference voltage terminal Vref of the buck-boost modulation management chip U2 is a fixed value. When the voltage of the voltage adjustment terminal VA > Vref, the buck-boost modulation management chip U2 works normally and the system charges normally; when VA < Vref, the buck-boost modulation management chip U2 will reduce the input current to maintain the charging input voltage at the set value Vtarget. Vtarget and Vref are in a proportional relationship, and the coefficient is a, Vtarget = a * Vref.

[0040] In addition, the RC filter circuit includes a fourth resistor R4 and a first capacitor C1. One end of the fourth resistor R4 is connected to the reference voltage terminal U2_Verf and the other end is connected to the voltage adjustment terminal; one end of the first capacitor C1 is connected to the reference voltage terminal U2_Verf and the other end is grounded. In this embodiment, the fourth resistor R4 and the first capacitor C1 together form an RC filter loop to smooth and filter the VA voltage to the reference voltage terminal Vref of the buck-boost modulation management chip U2.

[0041] The switch circuit 130 includes a MOS tube, the gate of the MOS tube is connected to the control output terminal U1_PWM, the drain is connected to the switch circuit 130, and the source is grounded. A fifth resistor R5 is also connected between the gate of the MOS tube and the control output terminal U1_PWM. The switch circuit 130 also includes a sixth resistor R6, one end of the sixth resistor R6 is connected to the gate of the MOS tube, and the other end of the sixth resistor R6 is connected to the power ground. In this embodiment, the regulation circuit 120 is regulated by the switch circuit 130. Specifically, it includes: when the MOS tube is not turned on, the voltage of the voltage regulation terminal A is defined as Va: Va=(R5 / (R1+R5))*Vtarget; when the MOS tube Q1 is turned on, the voltage of the voltage regulation terminal A is defined as Vb: R and = R2*R5 / (R2+R5),

[0042] Vb=(Rparallel / (R1+Rparallel))*Vtarget; when the MOS tube Q1 is modulated by the main control chip U1, the equivalent duty cycle is: D={[(Va-Vb)-(Vref-Vb)] / (Va-Vb)}*100%.

[0043] When the main control chip U1 controls Q1 to turn on with a duty cycle D, the voltage at point A can be dynamically adjusted, so that the buck-boost modulation management chip U2 can dynamically follow the output of the charger according to the current minimum output voltage limit of the charger, thereby achieving a constant voltage output effect of the charger.

[0044] The monitoring circuit 110 includes a monitoring chip U3, which includes a monitoring input terminal U3_CHARGE_VOL and a monitoring output terminal U3_COM. The monitoring input terminal U3_CHARGE_VOL is connected to the charging input terminal of the charger, and the monitoring output terminal U3_COM is connected to the signal input terminal U1_COM. The monitoring chip U3 can be a protocol IC, wherein the monitoring chip U3 and the main control chip U1 have a protocol handshake, so that the voltage input value of the charger detected by the monitoring chip U3 can be output to the main control chip U1 for judgment.

[0045] In addition, the charger is a charger that supports the PD protocol, the QC protocol, or the SCP protocol, and the voltage input value of the charger is any value between 5V and 28V. This circuit can be applied to chargers with fast charging protocols, such as chargers that support fast charging protocols like PD, QC, and SCP. When the charger outputs voltages in different grades, such as 5V / 9V / 12V / 15V / 20V / 28V, etc., the buck-boost modulation management chip U2 adaptively follows the output of the charger. In the embodiment of the present invention, a switch circuit 130 is set, and according to the monitored voltage input value, a PWM signal is output to the switch circuit 130 to dynamically adjust the adjustment circuit 120. The effect of adaptively following the output voltage of the charger is achieved, ensuring that the charger can output a constant voltage continuously and stably; and the circuit is simple. Through this circuit solution, the production cost can be greatly reduced, and it can be applied to a wide range of industrial production.

[0046] Embodiment 3:

[0047] The present invention provides an electrical device 310, such as Figure 3 as shown. The electrical device 310 includes a housing and a circuit board 320 disposed inside the housing. The circuit board 320 integrates the PWM-based charging voltage following circuit as described above. In this embodiment, it can be applied to chargers or devices with charging functions. Through this circuit, charging voltage following is performed to protect the voltage stability of the charging device. In this application, the master control chip U1 and the monitoring chip U3 perform protocol handshake, communicate to obtain and monitor the current output voltage Vin of the charger in real time, and set the current minimum output limit voltage Vtarget of the charger = Vin - 0.5V. The master control chip U1 controls the on / off of the MOS transistor through PWM modulation control signals to change the impedance of the voltage adjustment terminal A to the ground, and realizes the dynamic adjustment of the voltage VA at the voltage adjustment terminal. The reference voltage Vref at the reference voltage terminal of the buck-boost modulation management chip U2 is a fixed value. When VA > Vref, U1 works normally and the system charges normally; when VA < Vref, the buck-boost modulation management chip U2 will reduce the input current to maintain the charging input voltage at the set value Vtarget. Vtarget and Vref are in a proportional relationship, and the coefficient is a, Vtarget = a * Vref. In the embodiment of the present invention, a switch circuit 130 is set, and according to the monitored voltage input value, a PWM signal is output to the switch circuit 130 to dynamically adjust the adjustment circuit 120. The effect of adaptively following the output voltage of the charger is achieved, ensuring that the charger can output a constant voltage continuously and stably; and the circuit is simple. Through this circuit solution, the production cost can be greatly reduced, and it can be applied to a wide range of industrial production.

[0048] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. In addition, the embodiments of the present invention are not directed to any particular programming language.

[0049] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. Similarly, in order to simplify the present invention and help understand one or more of the various aspects of the present invention, in the above description of the exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Among them, the claims that follow the specific embodiments are hereby expressly incorporated into the specific embodiments, wherein each claim itself serves as a separate embodiment of the present invention.

[0050] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

[0051] It should be noted that the above embodiments illustrate the utility model rather than limit the utility model, and those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation on the claims. The word "comprising" does not exclude the existence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the existence of multiple such elements. The utility model can be implemented by means of hardware including several different elements and by means of appropriately programmed computers. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words can be interpreted as names. The steps in the above embodiments should not be understood as limitations on the order of execution unless otherwise specified.

Claims

1. A charging voltage follower circuit based on PWM, characterized in that: The circuit comprises: A monitoring circuit is connected to a charging input terminal of the charger to monitor a voltage input value of the charger; A regulating circuit connected to the charging input terminal to adjust the voltage value of the reference voltage terminal of the reference circuit; A reference circuit is connected to the regulating circuit and outputs a reference voltage value to the regulating circuit; A switch circuit connected to the regulating circuit to modulate the change of the impedance of the regulating circuit to ground; And a main control chip is provided with a signal input terminal and a control output terminal, the signal input terminal is connected to the monitoring circuit, the control output terminal is connected to the switching circuit, and according to the monitored voltage input value, a PWM signal is output to the switching circuit to dynamically adjust the regulation circuit.

2. The PWM-based charging voltage follower circuit according to claim 1, characterized in that: The regulating circuit is provided with a voltage regulating end, and the regulating circuit further comprises a first resistor, a second resistor, and a third resistor, and the first resistor, the second resistor, and the third resistor are respectively connected in parallel to the voltage regulating end; The other end of the first resistor is connected to the charging input terminal, the other end of the second resistor is connected to the switch circuit, and the other end of the third resistor is grounded; The voltage regulating terminal is also connected to the reference circuit.

3. The PWM-based charging voltage follower circuit according to claim 2, characterized in that: The reference circuit includes a buck-boost modulation management chip and an RC filter circuit. The buck-boost modulation management chip is provided with a reference voltage terminal, and the reference voltage terminal is connected to the voltage regulation terminal through the RC filter circuit.

4. The PWM-based charging voltage follower circuit according to claim 3, characterized in that: The RC filter circuit includes a fourth resistor and a first capacitor, one end of the fourth resistor is connected to the reference voltage terminal and the other end is connected to the voltage regulation terminal; one end of the first capacitor is connected to the reference voltage terminal and the other end is grounded.

5. The PWM-based charging voltage follower circuit according to any one of claims 2 to 4, characterized in that: The switch circuit comprises a MOS tube, a gate of the MOS tube is connected to the control output end, a drain is connected to the switch circuit, and a source is grounded.

6. The PWM-based charging voltage follower circuit according to claim 5, characterized in that: A fifth resistor is also connected between the gate of the MOS tube and the control output end.

7. The PWM-based charging voltage follower circuit according to claim 5, characterized in that: The switch circuit further includes a sixth resistor, one end of the sixth resistor is connected to the gate of the MOS tube, and the other end of the sixth resistor is connected to the power ground.

8. The PWM-based charging voltage follower circuit according to claim 1, characterized in that: The monitoring circuit includes a monitoring chip, and the monitoring chip includes a monitoring input terminal and a monitoring output terminal. The monitoring input terminal is connected to the charging input terminal of the charger, and the monitoring output terminal is connected to the signal input terminal.

9. The PWM-based charging voltage follower circuit according to claim 1, characterized in that: The charger is a charger that supports the PD protocol, the QC protocol, or the SCP protocol, and a voltage input value of the charger is any value between 5V and 28V.

10. An electrical device, characterized in that: It comprises a shell and a circuit board arranged inside the shell, wherein the circuit board is integrated with the PWM-based charging voltage follower circuit as described in any one of claims 1 to 9.

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