CN218482777U

CN218482777U - External simulation soft start circuit

Info

Publication number: CN218482777U
Application number: CN202221900519.1U
Authority: CN
Inventors: 王强; 郑曙光
Original assignee: Fish Green Energy Technology Ningbo Co ltd
Current assignee: Feishi Green Energy Electrical Technology Tianjin Co ltd
Priority date: 2022-07-22
Filing date: 2022-07-22
Publication date: 2023-02-14
Anticipated expiration: 2032-07-22

Abstract

The utility model discloses an external simulation soft start circuit, including power ic pin one, power ic pin one is connected with power ic pin two, power ic pin two is connected with power ic pin three, power ic pin two all is connected with the comparator with power ic pin three. The utility model discloses a substantive effect is: the comparator is combined with the DAC and the PWM output by the timer to form a current control loop cycle by cycle, the PWM is a pulse modulation width modulation interface, the PWM is a digital signal similar to a sine wave, and the analog circuit is controlled in a digital mode, so that the cost and the power consumption of the system can be greatly reduced, and the function of adjusting the starting time can be achieved.

Description

External simulation soft start circuit

Technical Field

The utility model relates to a power soft start technical field, in particular to external simulation soft start circuit.

Background

The input circuit of the switching power supply mostly adopts a rectification and capacitance filter circuit. At the moment of closing an input circuit, because an initial voltage on a capacitor is zero, a large instantaneous impact current can be formed, particularly for a high-power switching power supply, and the amplitude of the impact current at the moment of switching on the power supply often causes the input fuse to be blown, and sometimes even causes contacts of a closing switch to be burned out.

For example, chinese patent CN205883041U, published 2016, 8, and 11 days, the utility model discloses a soft start circuit, which comprises a bias circuit, a capacitor charging and discharging circuit, and an operational amplifier circuit, wherein the bias circuit, the capacitor charging and discharging circuit, and the operational amplifier circuit are electrically connected in sequence; the bias circuit is used for providing bias current; the capacitor charging and discharging circuit generates a constant current through the mirror image to charge the capacitor; the operational amplifier circuit is used for outputting stable reference voltage; the bias circuit comprises a bias current source Ibs, a power supply voltage VDD and a PMOS (P-channel metal oxide semiconductor) tube MP1; the source electrode of the PMOS pipe MP1 is connected with a power voltage VDD; the grid electrode of the PMOS tube MP1 is connected with a capacitor charging and discharging circuit; the drain electrode of the PMOS tube MP1 is connected with the grid electrode and the input end of the bias current source Ibs; the output of the bias current source Ibs is connected to ground. Although the current is limited during the starting process of the circuit, the problems of complex circuit design, incapability of adjusting time and the like exist.

Disclosure of Invention

The utility model discloses there is the technical problem that circuit design is complicated and can not adjust time to present soft start circuit, takes the PWM of comparator and DAC and timer output to combine together, constitutes the current control return circuit who cycle by cycle to reach the effect of adjusting the start time.

In order to solve the technical problem, the utility model discloses the technical scheme who takes does: an external simulation soft start circuit comprises a first power supply ic pin, wherein the first power supply ic pin is connected with a second power supply ic pin, the second power supply ic pin is connected with a third power supply ic pin, and the second power supply ic pin and the third power supply ic pin are both connected with a comparator. The comparator is to compare two or more data items to determine whether they are equal or determine the magnitude relationship and the arrangement order between them, which is called comparison. The circuit or device that can implement this comparison function is called a comparator. The comparator is a circuit that compares the analog voltage signal with a reference voltage. The two inputs of the comparator are analog signals and the output is a binary signal 0 or 1. The output remains constant when the difference in input voltages increases or decreases and the sign remains constant. The performance of the comparator includes output delay time: including the propagation delay of the signal through the components and the rise and fall times of the signal. Different factors, such as temperature and capacitance, have an effect on the comparator delay time. And a first power supply ic pin is a VREF reference voltage, a second power supply ic pin is a COMP pin, and a third power supply ic pin is an FB feedback voltage.

Preferably, the first pin of the power supply ic is connected with a diode and a resistor respectively, and the diode and the resistor are both connected with a capacitor. The diode is an electronic device made of semiconductor materials, plays a role in stabilizing voltage, and can bear higher reverse voltage, so that the effect of reverse blocking is played. The diode has a one-way conduction function, can play a role in switching and isolation, can generate positive electricity when current flows, and can generate unsmooth electricity when negative electricity flows, so that an isolation effect is achieved.

Preferably, the first power supply pin is connected with a first impedance, and two ends of the first impedance are respectively connected with a second power supply pin and a third power supply pin; and the first pin of the power supply ic is connected with a reference voltage, and the third pin of the power supply ic is connected with a feedback voltage. And a second pin of the power supply ic is a COMP pin, the COMP pin is an error amplifier compensation pin, and an RC compensation network is connected between the pin and an inverting input end (VFB) of the error amplifier to improve the performance of the error amplifier.

Preferably, the second pin of the power supply ic is connected with a triode, and the triode is connected with a capacitor. The triode is a 2N2907PNP triode which is one of basic semiconductor devices, the main structure of the triode is that two similar PN junctions are manufactured on a basic chip of a semiconductor, then a positive semiconductor is divided into three parts, and the connection between the semiconductors is utilized to carry out current collection work, so that large static direct current is controlled through small alternating current input.

Preferably, the triode and the capacitor are both grounded. The capacitor is also called "capacitance", and refers to the storage amount of free charges under a given potential difference, the charges are forced to move in an electric field, when a medium is arranged between conductors, the movement of the charges is blocked, so that the charges are accumulated on the conductors, and the accumulated storage of the charges is caused, and the stored charge amount is called as the capacitor.

Preferably, the ic pin three and the impedance one are both connected with the impedance two. And a third pin of the power supply ic is an FB feedback voltage, the output voltage is divided and then connected to the pin, the pin is connected with a comparator inside the chip and is compared with the VERF, if the feedback voltage is low, the duty ratio of the switch is increased, otherwise, the duty ratio is reduced, and the purpose of stabilizing the voltage is achieved. The access point of the FB feedback voltage electric equipment divides voltage, so that the voltage drop of a line can be reduced, and the large current is obvious.

Preferably, the second impedance is connected to the voltage output terminal. The VOUT output voltage is the maximum voltage output by the electronic component. The output voltage refers to the magnitude of the voltage in the direction of the output current of the electronic device.

Preferably, the voltage value of the first pin of the power supply ic is 5V. The first pin of the power supply ic is a VREF reference voltage, and VREF is a voltage which is irrelevant to load, power supply, temperature drift, time and the like and can be kept constant all the time in a circuit. Refers to the voltage value used as a reference when measuring the voltage value.

The utility model discloses a substantive effect is: the comparator is combined with the DAC and the PWM output by the timer to form a cycle-by-cycle current control loop, the PWM is a pulse modulation width modulation interface, the PWM is a digital signal similar to a sine wave, the cost and the power consumption of a system can be greatly reduced by controlling the analog circuit in a digital mode, and the function of adjusting the starting time can be achieved.

Drawings

Fig. 1 is a schematic diagram of the circuit structure of the present invention.

Wherein: 1, a first pin of a power supply ic; 2, power ic pin two; 3, power ic pin two; 4, impedance is one; 5, a comparator; 6, impedance two; 7, a triode; 8, a diode; 9, resistance; 10, a capacitor; 11, and a voltage output terminal.

Detailed Description

The following provides a more detailed description of the present invention, with reference to the accompanying drawings. An external analog soft start circuit is disclosed, as shown in fig. 1, and includes a first power ic pin 1, the first power ic pin 1 is connected to a second power ic pin 2, the second power ic pin 2 is connected to a third power ic pin 3, and both the second power ic pin 2 and the third power ic pin 3 are connected to a comparator 5. And the output end of the comparator is connected with the second power supply ic pin. The comparator compares two or more data items to determine whether they are equal or determine the magnitude relationship and the arrangement order between them, which is called comparison. The circuit or device that can implement this comparison function is called a comparator. The comparator is a circuit that compares the analog voltage signal with a reference voltage. The two inputs of the comparator are analog signals and the output is a binary signal 0 or 1. The output remains constant when the difference in input voltages increases or decreases and the sign remains constant. The performance of the comparator includes output delay time: including the propagation delay of the signal through the components and the rise and fall times of the signal. Various factors such as temperature and capacitance have an effect on the delay time of the comparator. And a first power supply ic pin is a VREF reference voltage, a second power supply ic pin is a COMP pin, and a third power supply ic pin is an FB feedback voltage.

The first power supply ic pin 1 is connected to a diode 8 and a resistor 9, respectively, and the diode 8 and the resistor 9 are both connected to a capacitor 10. The diode is an electronic device made of semiconductor materials, plays a role in stabilizing voltage, and can bear higher reverse voltage, so that the effect of reverse blocking is played. The diode has a one-way conductive function, can play a role in switching and isolation, and can generate positive electricity when current flows, and the diode can generate unsmooth situation when negative electricity exists, so that the isolation effect is achieved. The diode is connected in parallel with the resistor, and the diode and the resistor form a whole which is respectively connected in series with the capacitor and the power ic pin 1. The cathode of the diode is connected with a first pin of the power supply ic, and the anode of the diode is connected with the capacitor.

The first power supply ic pin 1 is connected with a first impedance 4, and two ends of the first impedance 4 are respectively connected with the second power supply ic pin 2 and the third power supply ic pin 3. And a second pin of the power supply ic is a COMP pin, the COMP pin is an error amplifier compensation pin, and an RC compensation network is connected between the pin and an inverting input end (VFB) of the error amplifier to improve the performance of the error amplifier.

And the second impedance 6 is connected with the voltage output end. The VOUT output voltage is the maximum voltage output by the electronic component. The output voltage refers to the magnitude of the voltage in the direction of the output current of the electronic device. Since the input and output voltages of all devices are not equal, there is a voltage drop in the process.

Power ic pin one 1 has a voltage value of 5V. The first pin of the power supply ic is a VREF reference voltage, and VREF is a voltage which is irrelevant to load, power supply, temperature drift, time and the like and can be kept constant all the time in a circuit. Refers to the voltage value used as a reference when measuring the voltage value. After the power supply IC supplies power, the reference voltage value of the reference voltage is 5V.

Power ic pin three 3 and impedance one 4 are both connected to impedance two 6. And a third pin of the power supply ic is an FB feedback voltage, the output voltage is divided and then connected to the pin, the pin is connected with a comparator inside the chip and is compared with the VERF, if the feedback voltage is low, the duty ratio of the switch is increased, otherwise, the duty ratio is reduced, and the purpose of stabilizing the voltage is achieved. The access point of the FB feedback voltage electric equipment divides voltage, so that the voltage drop of a line can be reduced, and the large current is obvious. After the power supply IC supplies power, the signal fed back to the FB is higher than the FB reference value and is generally 1.25 (slightly different according to different chips), although the output of the error comparator is high level, the high level is invalid because the 2N2907PNP triode is in a conducting state, and the power supply IC chip does not have PWM output.

And the second power supply ic pin 2 is connected with a triode 7, the triode 7 is connected with a capacitor 10, and the triode 7 and the capacitor 10 are both grounded. The triode is a 2N2907PNP triode, the Base end of a 2N2907PNP triode is connected with the capacitor, the Collector end of the 2N2907PNP triode is grounded, and the Emitter end of the 2N2907PNP triode is connected with the first pin of the power supply ic. The triode is one of basic devices of semiconductors, the main structure of the triode is that two similar PN junctions are manufactured on a basic chip of the semiconductor, then a positive semiconductor is divided into three parts, and the connection between the semiconductors is utilized to collect current, so that large static direct current is controlled through small alternating current input. The capacitor is also called "capacitance", and refers to the amount of stored free charges under a given potential difference, the charges are forced to move in an electric field, when a medium exists between conductors, the movement of the charges is blocked, so that the charges are accumulated on the conductors, resulting in the accumulated storage of the charges, and the amount of stored charges is called as the capacitor. After the power supply IC supplies power, the voltage at two ends of the capacitor gradually increases along with the time, the conduction state of the 2N2907PNP triode gradually weakens, the PWM output gradually increases in the process, and the soft start of the power supply is completed until the 2N2907PNP triode is turned off.

The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention.

Claims

1. An external simulation soft start circuit is characterized by comprising a power ic pin I (1), wherein the power ic pin I (1) is connected with a power ic pin II (2), the power ic pin II (2) is connected with a power ic pin III (3), and the power ic pin II (2) and the power ic pin III (3) are both connected with a comparator (5).

2. An external analog soft start circuit as claimed in claim 1, wherein the first power ic pin (1) is connected to a diode (8) and a resistor (9), respectively, and the diode (8) and the resistor (9) are both connected to a capacitor (10).

3. An external analog soft start circuit according to claim 1 or 2, wherein the first power ic pin (1) is connected to a first impedance (4), and two ends of the first impedance (4) are respectively connected to the second power ic pin (2) and the third power ic pin (3); and a first pin (1) of the power supply ic is connected with a reference voltage, and a third pin (3) of the power supply ic is connected with a feedback voltage.

4. An external analog soft start circuit according to claim 3, wherein the second pin (2) of the power ic is connected to a transistor (7), and the transistor (7) is connected to a capacitor (10).

5. An external analog soft start circuit according to claim 4, wherein the transistor (7) and the capacitor (10) are both connected to ground.

6. An external analog soft start circuit as claimed in claim 1 wherein the power ic pin three (3) and impedance one (4) are connected to impedance two (6).

7. An external analog soft start circuit according to claim 6, characterized in that the second impedance (6) is connected to the voltage output (11).

8. An external analog soft start circuit as claimed in claim 1 or 2, wherein the voltage value of the first (1) pin of the power ic is 5V.