CN109936290B - Switching power supply circuit - Google Patents
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- CN109936290B CN109936290B CN201910356534.0A CN201910356534A CN109936290B CN 109936290 B CN109936290 B CN 109936290B CN 201910356534 A CN201910356534 A CN 201910356534A CN 109936290 B CN109936290 B CN 109936290B
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Abstract
The integrated circuit for the switching power supply circuit integrates a sampling network in a chip, then utilizes test equipment to program and automatically trim when a wafer is tested, and simultaneously is matched with an internal temperature compensation circuit to realize that the precision in the whole temperature range of-40-85 ℃ is better than +/-0.5%. Different battery voltages and battery cell numbers are realized by adopting a resistor stepping selection mode, and a chip can be provided with a battery cell number selection resistor pin and a battery voltage selection resistor pin.
Description
Technical Field
The invention belongs to the technical field of electronic circuits, and particularly relates to a switching power supply circuit.
Background
In order to prevent damage or safety accidents caused by overcharging of a lithium battery, it is generally required to strictly control the output voltage accuracy of an AC/DC power supply so as to prevent the overcharging effectively when a charging system is in operation or a post-stage charging switching power supply circuit is out of order. Currently, industry manufacturers generally require that the power output accuracy be better than ±0.5%, for example, 5 knots of 4.2V, a typical output voltage is 21V, the upper limit is 21.105V, and the lower limit is 20.895V.
At present, TL431 with the precision of +/-0.5% is generally used as a reference, and a resistor with the precision of +/-1% is used as a sample, so that the boundary precision is only +/-2.5%, and is far lower than the requirement of +/-0.5%. Therefore, in production, a plurality of resistors are generally connected in parallel to be used as sampling, and then the number of the resistors is manually adjusted according to a test result to achieve the accuracy requirement of +/-0.5%, so that the operation efficiency is poor, and the cost is high.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a switching power supply circuit, which aims to solve the problems of poor operation efficiency and high cost caused by the fact that a plurality of resistors are generally connected in parallel to be used as sampling when the traditional switching power supply is produced, and the number of the resistors is manually adjusted to achieve the accuracy requirement of +/-0.5%.
A first aspect of an embodiment of the present invention provides a switching power supply circuit, including:
the voltage conversion module is connected to the input voltage, outputs a first direct-current voltage and is used for carrying out voltage conversion on the input voltage;
the output end of the PWM control chip is connected with the voltage conversion module;
The sampling module is connected with the output of the voltage conversion module and comprises a switching power supply control chip, a compensation unit connected with the switching power supply control chip and a load parameter setting unit connected with the switching power supply control chip, wherein the switching power supply control chip is used for obtaining a sampling signal according to a preset load parameter of the load parameter setting unit and the first direct current voltage, and the compensation unit is used for carrying out voltage current compensation on the sampling signal;
The input end of the optical coupler feedback module is connected with the output end of the sampling module, the output end of the optical coupler feedback module is connected with a feedback pin of the PWM control chip, the optical coupler feedback module is used for feeding back the sampling signal to the PWM control chip, and the PWM control chip accurately adjusts the first direct current voltage according to the sampling signal so as to be matched with a load.
In one embodiment, the switching power supply control chip includes:
Grounding feet;
A battery number setting pin for connecting the load parameter setting unit to set the number of parallel loads;
A battery voltage setting pin for connecting the load parameter setting unit to set rated voltage of each load;
the LED driving pins are used for driving the LED lamps;
The power supply pin is used for accessing power supply voltage;
the optocoupler driving pin is used for being connected with the optocoupler feedback module and outputting the sampling signal;
A voltage loop compensation pin connected to the compensation unit; and
And the current sampling pin is used for being connected with the first direct-current voltage.
In one embodiment, the switching power supply control chip includes: the device comprises a first current source, a second current source, an analog-to-digital conversion circuit, a reference bias circuit, an optocoupler driving circuit and a lamp turning driving circuit;
the first input end of the analog-to-digital conversion circuit is connected with the first current source and the battery section number setting pin, the second input end of the analog-to-digital conversion circuit is connected with the second current source and the battery voltage setting pin, the input end of the reference bias circuit is connected with the output end of the analog-to-digital conversion circuit, the first output end of the reference bias circuit is connected with the first input end of the optocoupler driving circuit to provide a voltage reference signal, the second output end of the reference bias circuit is connected with the second input end of the optocoupler driving circuit to provide a current reference signal, the third input end of the optocoupler driving circuit is connected with the power supply pin through a first voltage dividing resistor and is grounded through a second voltage dividing resistor, the voltage loop compensation pin is connected with the third input end of the optocoupler driving circuit, the current sampling pin is connected with the fourth input end of the optocoupler driving circuit and the input end of the switching lamp driving circuit, the output end of the optocoupler driving circuit is connected with the optocoupler driving pin, and the output end of the switching lamp driving circuit is connected with the LED driving pin.
In one embodiment, the load is a battery, and the switching power supply control chip further includes:
A temperature detecting pin for detecting a battery temperature;
the switch driving pin is used for switching off the output of the first direct-current voltage after the battery is charged and fully charged;
the communication pin is used for communicating with the outside, and identifying whether the accessed battery is in compliance or not so as to determine whether to charge or not; and
And the voltage output pin is used for providing a regulated power supply for the outside.
In one embodiment, the optocoupler driving circuit includes:
A voltage error amplifier, wherein the non-inverting input end of the voltage error amplifier is used as the third input end of the optocoupler driving circuit, the inverting input end of the voltage error amplifier is used as the first input end of the optocoupler driving circuit,
The non-inverting input end of the current error amplifier is used as a second input end of the optocoupler driving circuit, and the inverting input end of the current error amplifier is used as a fourth input end of the optocoupler driving circuit;
The grid electrode of the first NMOS tube is connected with the output end of the voltage error amplifier, and the source electrode of the first NMOS tube is grounded;
The grid electrode of the second NMOS tube is connected with the output end of the current error amplifier, the source electrode of the second NMOS tube is at the base, and the drain electrode of the first NMOS tube and the drain electrode of the second NMOS tube are connected together and serve as the output end of the optocoupler driving circuit.
In one embodiment, the load parameter setting unit includes a first preset resistor and a second preset resistor, the first preset resistor is connected between the battery node number setting pin and the ground, and the second preset resistor is connected between the battery voltage setting pin and the ground.
In one embodiment, the first preset resistance and the second preset resistance are 5% accurate.
In one embodiment, the compensation unit includes a voltage stabilizing compensation circuit connected between the voltage loop compensation pin and the optocoupler drive pin.
In one embodiment, the voltage regulation compensation circuit includes a first resistor and a first capacitor connected in series.
In one embodiment, the circuit further comprises a second capacitor connected in parallel with the first resistor and the first capacitor connected in series.
In one embodiment, the compensation unit comprises a constant current compensation circuit, and the constant current compensation circuit is connected with the current sampling pin and the optocoupler driving pin.
In one embodiment, the constant current compensation circuit includes a second resistor and a third capacitor connected in series between the current sampling pin and the optocoupler driving pin, and a fourth capacitor connected between the current sampling pin and ground.
In one embodiment, the optocoupler feedback module includes a photocoupler, a first current limiting resistor and a third resistor, wherein an input end of a light emitter of the photocoupler is connected with an output of the voltage conversion module through the third resistor, an output end of the light emitter of the photocoupler is used as an input end of the optocoupler feedback module, and the first current limiting resistor is connected between the input end and the output end of the light emitter.
The switching power supply circuit uses the high integration advantage of an integrated circuit, integrates a sampling network in a chip, then utilizes test equipment to program and automatically trim when a wafer is tested, and simultaneously cooperates with a compensation circuit to realize that the precision is better than +/-0.5% in the full temperature range of-40-85 ℃. In addition, different load voltages and the number of parallel connections are realized by adopting a load parameter preset mode, manual trimming of a power supply production line is avoided, the operation efficiency is improved, the performance is improved, and the cost is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a switching power supply circuit according to an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of an example switching power supply control chip in the switching power supply circuit shown in FIG. 1;
FIG. 3A is a schematic diagram of an example circuit on the high side of the switching power supply circuit shown in FIG. 1;
FIG. 3B is a schematic diagram of one example low side circuit of the switching power supply circuit shown in FIG. 1;
fig. 4 is another low side exemplary circuit schematic of the switching power supply circuit shown in fig. 1.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1, a schematic structural diagram of a switching power supply circuit according to an embodiment of the present invention is shown, for convenience of explanation, only the portions related to the embodiment are shown, and the details are as follows:
the switching power supply circuit includes a voltage conversion module 110, a PWM control chip 120, a sampling module 130, and an optocoupler feedback module 140.
The voltage conversion module 110 is connected to the input voltage VI, the voltage conversion module 110 outputs a first direct current voltage VO, and the voltage conversion module 110 is configured to perform voltage conversion on the input voltage VI; the voltage conversion module 110 may be an isolated DC/DC converter or a non-isolated DC/DC converter, and the input voltage VI may be a direct DC input or an ac input and then rectified to a DC, see fig. 3A and 3B. The output end of the PWM control chip 120 is connected with the voltage conversion module 110; the PWM control chip 120 is configured to output a PWM signal to control the voltage conversion module 110 to operate.
The sampling module 130 is connected with the output of the voltage conversion module 110, the sampling module 130 comprises a switching power supply control chip 131, a compensation unit 132 connected with the switching power supply control chip 131 and a load parameter setting unit 133 connected with the switching power supply control chip 131, the switching power supply control chip 131 is used for obtaining a sampling signal according to a preset load parameter and a first direct current voltage VO of the load parameter setting unit 133, and the compensation unit 132 is used for performing voltage current compensation on the sampling signal; the optical coupler feedback module 140, the input end of the optical coupler feedback module 140 is connected with the output end of the sampling module 130, the output end of the optical coupler feedback module 140 is connected with the feedback pin of the PWM control chip 120, the optical coupler feedback module 140 is used for feeding back a sampling signal to the PWM control chip 120, and the PWM control chip 120 accurately adjusts the first direct current voltage VO according to the sampling signal so as to match the load.
Specifically, the sampling module 130 is provided with the compensation unit 132 to form a high-precision constant voltage constant current loop, so that stable output voltage with precision superior to 0.5% can be realized without depending on external devices; in addition, the switch power supply control chip 131 is internally provided with an optocoupler driving circuit and is provided with independent feedback compensation pins, and system compensation matching can be performed outside, so that the compensation design under various power supply design conditions is adapted; the sampling module 130 is as low as 50mV constant current loop control threshold, so that the system sampling loss can be effectively reduced, the system efficiency can be improved, and the application meeting the energy efficiency requirement can be easily designed by matching with the minimum working current as low as 0.5 mA. The sampling module 130 can be matched with various PWM switches to construct an ultra-compact 0.5% high-precision charging power supply system.
Referring to fig. 2, the switching power supply control chip 131 includes a ground pin 1; a battery number setting pin 2 for connecting the load parameter setting unit 133 to set the number of parallel loads, for example, the load is a battery pack, or an LED lamp pack; a battery voltage setting pin 3 for connecting the load parameter setting unit 133 to set rated voltages of the respective loads; an LED driving pin 4 for driving the LED lamp; a power supply pin 5 for connecting to a power supply voltage; an optocoupler driving pin 6 for outputting a sampling signal connected with the optocoupler feedback module 140; a voltage loop compensation pin 7 connected to the compensation unit 132; and a current sampling pin 8 for connection to the first direct voltage VO. The switch power supply control chip 131 starts to work after being electrified and generates a required internal reference voltage signal, and the system can be satisfied by only adding a necessary decoupling capacitor C0 to a power supply terminal in use.
Referring to fig. 2, 3A and 3B, in one embodiment, the switching power supply control chip 131 includes: a first current source 1311, a second current source 1312, an analog-to-digital conversion circuit 1313, a reference bias circuit 1314, an optocoupler drive circuit 1315, and a turn-light drive circuit 1316; a first input end of the analog-to-digital conversion circuit 1313 is connected with the first current source 1311 and the battery node number setting pin 2, a second input end of the analog-to-digital conversion circuit 1313 is connected with the second current source 1312 and the battery voltage setting pin 3, an input end of the reference bias circuit 1314 is connected with an output end of the analog-to-digital conversion circuit 1313, a first output end of the reference bias circuit 1314 is connected with a first input end of the optocoupler driving circuit 1315 to provide a voltage reference signal, a second output end of the reference bias circuit 1314 is connected with a second input end of the optocoupler driving circuit 1315 to provide a current reference signal, a third input end of the optocoupler driving circuit 1315 is connected with the power supply pin 5 through a first voltage dividing resistor 1317 and is grounded through a second voltage dividing resistor 1318, the voltage loop compensation pin 7 is connected with a third input end of the optocoupler driving circuit 1315, the current sampling pin 8 is connected with a fourth input end of the optocoupler driving circuit 1315 and an input end of the light conversion driving circuit 1316, and an output end of the light conversion driving circuit 1315 is connected with the light driving pin 6.
Referring to fig. 3A and 4, the high-side example circuit of the switching power supply circuit shown in fig. 3A may form a complete switching power supply circuit with the low-side example circuit of the switching power supply circuit shown in fig. 4, that is, the low-side example circuit of the switching power supply circuit shown in fig. 4 may be replaced with the low-side example circuit of the switching power supply circuit shown in fig. 3B.
In a further embodiment, referring to fig. 3A and fig. 4, the switching power supply control chip 131 further includes a communication pin 13, a temperature detection pin 14, and a switch driving pin 12, so that the switching power supply can further add communication and external sensing functions, when the battery temperature is lower than a certain value or higher than a certain value, the system refuses to charge, and the system can be connected to the temperature-sensitive resistor voltage divider network to automatically close the output when the external temperature reaches the protection action threshold value, thereby realizing over-temperature protection. The communication pin 13 communicates with the outside for identifying whether the connected battery is compliant to determine whether to charge. The switch driving pin 13 is configured to turn off the output of the first dc voltage V0 after the battery is charged and full, and specifically, a switch tube M1 may be disposed at the output positive electrode of the low-voltage side of the voltage conversion module 110, and the switch driving pin 12 controls the switch tube M1 to control the output of the first dc voltage V0.
Referring to fig. 2, the optocoupler driving circuit 1315 includes a voltage error amplifier OP1, a current error amplifier OP2, a first NMOS transistor Q1 and a second NMOS transistor Q2.
The non-inverting input terminal of the voltage error amplifier OP1 is used as the third input terminal of the optocoupler driving circuit 1315, the inverting input terminal of the voltage error amplifier OP1 is used as the first input terminal of the optocoupler driving circuit 1315, the non-inverting input terminal of the current error amplifier OP2 is used as the second input terminal of the optocoupler driving circuit 1315, and the inverting input terminal of the current error amplifier OP2 is used as the fourth input terminal of the optocoupler driving circuit 1315; the grid electrode of the first NMOS tube Q1 is connected with the output end of the voltage error amplifier OP1, and the source electrode of the first NMOS tube Q1 is grounded; the gate of the second NMOS transistor Q2 is connected to the output terminal of the current error amplifier OP2, the source of the second NMOS transistor Q2 is grounded, and the drain of the first NMOS transistor Q1 and the drain of the second NMOS transistor are commonly connected and serve as the output terminal of the optocoupler driving circuit 1315. The switching power supply control chip 131 is internally provided with an optocoupler driving circuit 1315 for voltage and current dual-loop control, and sampling signals (adjusting signals) directly drive the optocoupler through the driving circuit so as to feed back adjusting information to the primary side PWM control chip 120, thereby realizing the stability of output voltage and the control of output constant current.
The turn lamp driving circuit 1316 includes a charge current detection and status detection circuit for indicating the present status when charged, typically an output constant current point size of 10% for a charge indication threshold current, when the output current is greater than 10%, the LED driving leg 4 is pulled down to ground internally, thereby lighting a charge indication lamp, and extinguishing a lamp connected in parallel thereto for indicating the full status by the charge indication lamp voltage clamping action; when the battery is gradually fully charged so that the charging current is reduced to less than 10%, the LED driving pin 4 is disconnected, so that the charging indicator lamp is extinguished, and meanwhile, the full-charge indicator lamp is lightened; the connection method can control the conversion of two states by using only one port. The LED connection is shown in fig. 2. The conversion circuit also has certain hysteresis, so that the output is prevented from being in a repeated switching state in critical conditions, for example, a power supply system with rated output of 21V/1.5A, namely 5 batteries with 4.2V, the charging indication threshold current is 150mA, and when the output current is larger than 151mA, the charging indication lamp is turned on, and meanwhile, the full indication lamp and the like are turned off; when the output current is less than 149mA, the charge indicator lamp is extinguished and the full indicator lamp is simultaneously lighted.
Referring to fig. 2 to 4, the load parameter setting unit 133 includes a first preset resistor 133A and a second preset resistor 133B, the first preset resistor 133A is connected between the battery node number setting pin 2 and the ground, and the second preset resistor 133B is connected between the battery voltage setting pin 3 and the ground.
The integrated circuit (switching power supply control chip 131) selects the number of battery cells, i.e., the rated output voltage of the system, through a simple external battery cell number setting resistor (first preset resistor 133A) which is independent of the accuracy of the output voltage, only a common resistor with an accuracy of 5% is required, and the system has a boundary redundancy of up to 10%, so that it can be ensured that the selection circuit can be stably set at a set value. For example, if the number of external battery cells is 5, the resistor is 30k, the 9.1k represents 7 battery cells, the 91k represents 3 battery cells, etc., and the resistor is automatically at the minimum number of battery cells or in a protection state when the resistor is opened.
The integrated circuit selects the rated voltage specification of a single battery through a simple external battery voltage setting resistor (a second preset resistor 133B) and embeds several battery voltage specifications, so that the integrated circuit is suitable for different types of battery systems, the battery voltage setting resistor is not affected by the precision of output voltage, the corresponding battery voltage setting resistor is only selected according to the battery type, and only 5% precision resistor is needed, meanwhile, the integrated circuit has a safe fault protection mechanism, can be in a protection state when the resistor is opened, and the output voltage is prevented from exceeding the set size. For example, if the single battery voltage is 4.2V, the external battery voltage setting resistor may be 68k, 91k for 4.25V/CELL, 9.1k for 5.30V/CELL, etc. The resistor is automatically at the lowest voltage or in a protected state when it is open. The selection resistor only needs to use a common resistor with 5% precision, and the voltage precision is completely irrelevant to the selection resistor.
Referring to fig. 2 to 4, the compensation unit 132 includes a voltage stabilizing compensation circuit 1321, and the voltage stabilizing compensation circuit 1321 is connected between the voltage loop compensation pin 7 and the optocoupler driving pin 6. In one embodiment, the voltage stabilizing compensation circuit 1321 is a first order compensation method, and includes a first resistor R1 and a first capacitor C1 connected in series. Further, the voltage stabilizing compensation circuit 1321 is a second order compensation mode, and further includes a second capacitor C2 connected in parallel with the first resistor R1 and the first capacitor C1 connected in series. The switching power supply control chip 131 is provided with an independent optocoupler driving pin 6, so that loop compensation work can be conveniently carried out outside.
In addition, the compensation unit 132 further includes a constant current compensation circuit 1322, and the constant current compensation circuit 1322 is connected to the current sampling pin 8 and the optocoupler driving pin 6. The constant current compensation circuit 1322 includes a second resistor R2 and a third capacitor C3 connected in series between the current sampling pin 8 and the optocoupler driving pin 6, and a fourth capacitor C4 connected between the current sampling pin 8 and ground. The output current information is obtained through the low-side current sampling resistor R0 outside the switching power supply control chip 131, and the internal current error amplifier is compared with the current sampling reference voltage (current reference signal) to generate a current error signal, so that the output is driven to change the sampling current, and constant output current control is realized. An isolation resistor (e.g., R6 in fig. 2) should also be connected in series between the current sampling resistor R0 and the current sampling pin 8 to apply the necessary current loop compensation network (e.g., R4, C3 in fig. 2) between the current sampling pin 8 and the optocoupler driving pin 6, and the necessary decoupling capacitance (e.g., C4 in fig. 2). The current compensation loop connection is shown in fig. 2.
Referring to fig. 2 to 4, the optocoupler feedback module 140 includes a photo-coupler U1, a first current-limiting resistor R4 and a third resistor R3, wherein an input end 1 of a light emitter of the photo-coupler U1 is connected to an output of the voltage conversion module 110 through the third resistor R3, an output end 2 of the light emitter of the photo-coupler U1 is used as an input end of the optocoupler feedback module 140, and the first current-limiting resistor R4 is connected between the input end 1 and the output end 2 of the light emitter. In general, a necessary current limiting resistor R4 should be connected in series with the optocoupler loop to limit the current of the optocoupler, so as to improve the service life of the optocoupler and promote the loop to be stable.
The switching power supply circuit in the embodiment realizes high precision by utilizing the proportion matching of the internal resistance of the integrated circuit and the temperature compensation design, which is better than 0.5%; the high integration characteristic of the integrated circuit is utilized, and the calibration is completed during the chip test without depending on external resistance; the load number can be set by externally selecting the resistor, and the selected resistor is irrelevant to the precision; the load voltage may be set by an external selection resistor, and the selection resistor is independent of accuracy. The factory does not need to be manually repaired and adjusted.
The switching power supply control chip 131 of the switching power supply circuit in the above embodiment has a voltage sampling voltage dividing network built therein, and has a power consumption of not more than 2mA under the condition that the output is not more than 40V.
Preferably, referring to fig. 2 and 4, the switching power supply control chip 131 is provided with a low dropout voltage regulator, and a voltage output pin 4 (replacing the LED driving pin) is further provided for outputting a stable dc voltage to the outside for use by a load (such as an LED lamp) outside the chip or a circuit in a battery pack, and the voltage range of the voltage output pin is set to be not lower than 2V and not higher than 5.5V. The voltage output pin 4 is connected with the anodes of the two LED lamps, and the switching power supply control chip is connected with the cathodes of the two LED lamps 15 and 16 by using the other two pins so as to control the lighting or extinguishing of the two LED lamps. The communication pin 13, the temperature detection pin 14 and the power output pin v+ may be integrated on one interface CN1 for transmitting data to an external device.
The comparison level of the current error amplifier built in the switching power supply control chip 131 can be set to a lower voltage to reduce the sampling loss, and the level is set below 500 mV.
The switch power supply circuit in the above embodiment has a safety protection function, and when the battery number selection or the battery voltage selection setting resistor is opened, the lowest gear corresponding to the battery number selection or the lowest gear corresponding to the battery voltage selection is selected, or the system is forced to enter a protection state.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (8)
1.A switching power supply circuit, comprising:
the voltage conversion module is connected to the input voltage, outputs a first direct-current voltage and is used for carrying out voltage conversion on the input voltage;
the output end of the PWM control chip is connected with the voltage conversion module;
The sampling module is connected with the output of the voltage conversion module and comprises a switching power supply control chip, a compensation unit connected with the switching power supply control chip and a load parameter setting unit connected with the switching power supply control chip, wherein the switching power supply control chip is used for obtaining a sampling signal according to a preset load parameter of the load parameter setting unit and the first direct current voltage, and the compensation unit is used for carrying out voltage current compensation on the sampling signal;
The input end of the optical coupler feedback module is connected with the output end of the sampling module, the output end of the optical coupler feedback module is connected with a feedback pin of the PWM control chip, the optical coupler feedback module is used for feeding back the sampling signal to the PWM control chip, and the PWM control chip accurately adjusts the first direct current voltage according to the sampling signal so as to match the load;
the switching power supply control chip includes:
A battery number setting pin for connecting the load parameter setting unit to set the number of parallel loads;
A battery voltage setting pin for connecting the load parameter setting unit to set rated voltage of each load;
the LED driving pins are used for driving the LED lamps;
The power supply pin is used for accessing power supply voltage;
the optocoupler driving pin is used for being connected with the optocoupler feedback module and outputting the sampling signal;
A voltage loop compensation pin connected to the compensation unit; and
The current sampling pin is used for connecting the first direct-current voltage;
the switching power supply control chip includes: the device comprises a first current source, a second current source, an analog-to-digital conversion circuit, a reference bias circuit, an optocoupler driving circuit and a lamp turning driving circuit;
The first input end of the analog-to-digital conversion circuit is connected with the first current source and the battery node number setting pin, the second input end of the analog-to-digital conversion circuit is connected with the second current source and the battery voltage setting pin, the input end of the reference bias circuit is connected with the output end of the analog-to-digital conversion circuit, the first output end of the reference bias circuit is connected with the first input end of the optocoupler driving circuit to provide a voltage reference signal, the second output end of the reference bias circuit is connected with the second input end of the optocoupler driving circuit to provide a current reference signal, the third input end of the optocoupler driving circuit is connected with the power supply pin through a first voltage dividing resistor and is grounded through a second voltage dividing resistor, the voltage loop compensation pin is connected with the third input end of the optocoupler driving circuit, the current sampling pin is connected with the fourth input end of the optocoupler driving circuit and the input end of the switching lamp driving circuit, the output end of the optocoupler driving circuit is connected with the optocoupler driving pin, and the output end of the switching lamp driving circuit is connected with the LED driving pin;
The load parameter setting unit comprises a first preset resistor and a second preset resistor, wherein the first preset resistor is connected between the battery node number setting pin and the ground, and the second preset resistor is connected between the battery voltage setting pin and the ground.
2. The switching power supply circuit of claim 1 wherein said switching power supply control chip further comprises:
And (5) grounding feet.
3. The switching power supply circuit according to claim 1 or 2, wherein the load is a battery, the switching power supply control chip further comprising:
A temperature detecting pin for detecting a battery temperature;
the switch driving pin is used for switching off the output of the first direct-current voltage after the battery is charged and fully charged;
the communication pin is used for communicating with the outside, and identifying whether the accessed battery is in compliance or not so as to determine whether to charge or not; and
And the voltage output pin is used for providing a regulated power supply for the outside.
4. The switching power supply circuit according to claim 3, wherein the optocoupler driving circuit includes:
A voltage error amplifier, wherein the non-inverting input end of the voltage error amplifier is used as the third input end of the optocoupler driving circuit, the inverting input end of the voltage error amplifier is used as the first input end of the optocoupler driving circuit,
The non-inverting input end of the current error amplifier is used as a second input end of the optocoupler driving circuit, and the inverting input end of the current error amplifier is used as a fourth input end of the optocoupler driving circuit;
The grid electrode of the first NMOS tube is connected with the output end of the voltage error amplifier, and the source electrode of the first NMOS tube is grounded;
The grid electrode of the second NMOS tube is connected with the output end of the current error amplifier, the source electrode of the second NMOS tube is at the base, and the drain electrode of the first NMOS tube and the drain electrode of the second NMOS tube are connected together and serve as the output end of the optocoupler driving circuit.
5. The switching power supply circuit according to claim 1, wherein the first preset resistance and the second preset resistance are 1% -5% accurate.
6. The switching power supply circuit according to claim 1, wherein the compensation unit includes a voltage-stabilizing compensation circuit connected between the voltage loop compensation pin and the optocoupler drive pin; the voltage stabilizing compensation circuit comprises a first resistor and a first capacitor which are connected in series.
7. The switching power supply circuit of claim 6 further comprising a second capacitor connected in parallel with the first resistor and the first capacitor connected in series.
8. The switching power supply circuit according to claim 1 or 5, wherein the compensation unit includes a constant current compensation circuit connected to the current sampling pin and the optocoupler driving pin; the constant current compensation circuit comprises a second resistor and a third capacitor which are connected in series between the current sampling pin and the optocoupler driving pin, and a fourth capacitor which is connected between the current sampling pin and the ground.
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| CN116204033B (en) * | 2023-04-27 | 2023-07-14 | 无锡前诺德半导体有限公司 | Parameter setting system of power supply device and design method thereof |
| CN116566175B (en) * | 2023-07-07 | 2023-09-22 | 上海类比半导体技术有限公司 | Voltage sampling circuit, switching power supply and chip |
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