CN209088812U - A kind of switching power supply of ultra-wide input range - Google Patents

Abstract

The utility model relates to the field of power supplies, in particular to a switching regulated power supply with an ultra-wide input range. Including the following modules: buck module, boost module, input filter module, output filter module, error acquisition module, mode control module, PWM wave generation module, over-temperature protection module, the input filter module, buck module, boost module, output filter module The modules are connected in sequence, the input end of the error collection module is connected with the output end of the output filtering module, the output end of the error collection module and the over-temperature protection module are all connected with the mode control module, and the mode control module is also connected with the PWM wave The generation module is connected, and the two outputs of the PWM wave generation module are respectively connected to the buck module and the boost module. This switching regulated power supply achieves an ultra-wide input range of 5-40V, and the output is stable at 12V. It is widely used in real life, especially in the field of automotive power supply.

Description

A switching regulated power supply with ultra-wide input range

technical field

The invention relates to the field of power supplies, in particular to a switching regulated power supply with an ultra-wide input range.

Background technique

When the linear regulated power supply on the market is applied to industry standard products with 12V input in the telecom market, its input range is usually 8-16V, or the ratio of the highest value to the lowest value of the input voltage is 2:1. But there are many applications that need to handle a wider input voltage range. For example, in some system applications the distributed input voltage has large transients and surges that last for a long time. Moreover, ordinary linear regulated power supplies generally have the problems of low conversion efficiency and large power loss.

The input voltage range of ordinary linear regulated power supply is narrow, and the parameters are generally designed with reference to the inherent standards of the industry.

When the difference between the input and output voltage of an ordinary linear regulated power supply is large, the power loss is large and the conversion power is very low.

Ordinary linear regulated power supply generally does not have over-temperature protection function, especially in the fields of automobiles, it is easy to cause safety accidents due to overheating of batteries.

Utility model content

The utility model proposes a switching regulated power supply with an ultra-wide input range, which can solve the above-mentioned problems well. It is widely used in application fields, especially in the field of automotive vehicle power supply.

The technical scheme adopted by the utility model is as follows:

A switching regulated power supply with an ultra-wide input range, comprising the following modules: a buck module, a boost module, an input filter module, an output filter module, an error acquisition module, a mode control module, a PWM wave generation module, and an over-temperature protection module;

The input filter module, the buck module, the boost module, and the output filter module are connected in sequence, the input end of the error collection module is connected to the output end of the output filter module, and the output end of the error collection module and the over-temperature protection module are connected to the output end of the output filter module. The mode control module is connected, and the mode control module is also connected with the PWM wave generation module. The two outputs of the PWM wave generation module are respectively connected to the buck module and the boost module and control the buck module and boost through the generated drive pulses. The working status of the module.

Wherein, the input filtering module includes an electrolytic capacitor and a chip capacitor, and the electrolytic capacitor and the chip capacitor are connected in parallel for decoupling the chip input pin V _IN .

Wherein, the electrolytic capacitor is 10μF, and the chip capacitor is 100nF.

Wherein, the output filtering module includes two chip capacitors and one tantalum capacitor, and the chip capacitor and the tantalum capacitor are connected in parallel, and are used for filtering the output voltage regulation signal to further reduce the ripple of the output voltage.

Among them, the chip capacitor is 470nF, and the tantalum capacitor is 68μF.

The buck module uses a vehicle-grade SQ4064EY type NMOS transistor, and the boost module uses a vehicle-grade SQ4410EY type NMOS transistor.

The rated voltage of the SQ4064EY-type NMOS transistor is 60V and the rated current is 12A; the rated voltage of the SQ4410EY-type NMOS transistor is 30V and the rated current is 15A.

Among them, the error acquisition module, mode control module, PWM wave generation module, and over-temperature protection module use an integrated chip with a model of LM25118 with a small number of peripheral circuits, and the input voltage of the integrated chip varies from 5 to 40V.

Beneficial effects:

1. Ultra-wide input range (5-40V);

2. High conversion efficiency;

3. With over-temperature protection function, it can avoid the failure caused by the high temperature of the power supply and improve the safety factor;

4. It has two working modes, which can automatically switch according to different input voltages, which reduces the power consumption of the system;

5. Use the voltage regulator output feedback to supply power to the chip, no external power supply is required.

Description of drawings

Figure 1 is a block diagram of the system composition.

Figure 2 is a circuit diagram of the system implementation.

In the picture:

1-input filtering module; 2-buck module; 3-boost module; 4-output filtering module; 5-error collecting module.

Detailed ways

In order to facilitate the understanding and implementation of the utility model by those of ordinary skill in the art, the present utility model will be described in further detail below with reference to the accompanying drawings and embodiments. to limit the present invention.

FIG. 1 is a block diagram of a system composition of a switching regulated power supply with an ultra-wide input range according to an embodiment of the present invention. It includes the following modules: buck module, boost module, input filter module, output filter module, error acquisition module, mode control module, PWM wave generation module, and over-temperature protection module.

The input filter module, the buck module, the boost module, and the output filter module are connected in sequence, the input end of the error collection module is connected to the output end of the output filter module, and the output end of the error collection module and the over-temperature protection module are connected to the output end of the output filter module. The mode control module is connected, and the mode control module is also connected with the PWM wave generation module. The two outputs of the PWM wave generation module are respectively connected to the buck module and the boost module and control the buck module and boost through the generated drive pulses. The working status of the module.

The working state of the buck module is controlled by one PWM wave, which is used to step down the input signal when the input signal is much larger than 12V.

The working state of the boost module is controlled by another PWM wave, which is used to boost the input signal when the input signal is lower than 12V.

The input filter module includes a 10μF electrolytic capacitor and a 100nF chip capacitor in parallel, which is used for decoupling the chip input pin VIN.

The output filter module includes two 470nF chip capacitors and a 68μF tantalum capacitor in parallel, which is used to filter the output voltage regulation signal and further reduce the ripple of the output voltage.

The error acquisition module is used to compare the output signal with a preset reference voltage after sampling to generate an error control voltage, and the relationship between the actual output voltage and the target output voltage can be determined by the magnitude and polarity of the error voltage.

The mode control module selects the working state of the circuit according to the error voltage output by the error collecting module, when the voltage is high, it works in the buck state, and when the voltage is close to or lower than 12V, it works in the buck-boost state.

The PWM wave generating module instantly adjusts the duty cycle of the two PWM waves according to different circuit working states, and adjusts the switching states of the NMOS transistors in the two circuits of the buck module and the boost module by adjusting the duty cycle.

Fig. 2 is the actual application circuit diagram of the system. The working state of the buck module is controlled by one PWM wave, which is used to step down the input signal when the input signal is much larger than 12V. The buck module consists of a vehicle-grade 60V NMOS tube (represented by Q1 in Figure 2), a step-down diode D2, a freewheeling diode D3, a large inductor L4 and three output filter capacitors C8, C9, E3 composition. By controlling the repeated turn-on and turn-off of the NMOS tube, the value of the output voltage is adjusted by the principle of a chopper. The inductor L4 is used to limit the current change rate. When the NMOS tube is turned on, the inductor L4 stores energy; when the NMOS tube is turned off, the inductor L4 converts the stored magnetic energy into electrical energy and continues to charge the three output filter capacitors C8, C9, and E3 , thus maintaining the continuity of the current. The step-down diode D2 is always in the conduction state, and the conduction voltage drop is used to partially step down the input voltage; the freewheeling diode D3 is only turned on when the NMOS tube is turned off, providing a freewheeling path for the circuit , so that the current of the inductor L4 does not decrease rapidly, and the breakdown of the switch tube caused by the high voltage induced by the inductor L4 is avoided.

The working state of the boost module is controlled by another PWM wave, which is used to boost the input signal when the input signal is lower than 12V. The boost module is composed of an NMOS tube with a withstand voltage of 30V (represented by Q2 in Figure 2), a diode D2, a large inductor L4 and three output filter capacitors C8, C9, and E3. By controlling the repeated turn-on and turn-off of the NMOS tube, the value of the output voltage is adjusted by the principle of a chopper. When the input voltage changes, the system obtains a stable output voltage by adjusting the duty ratio of the two control pulses.

Among them, the error acquisition module, mode control module, PWM wave generation module, and over-temperature protection module use an integrated chip with a model of LM25118 with a small number of peripheral circuits, and the input voltage of the integrated chip varies from 5 to 40V.

When the input signal voltage is much greater than 12V, the circuit works in the buck state, the NMOS transistor Q1 is in the on state, and the NMOS transistor Q2 is in the off state, which does not work in the circuit. The buck module circuit performs step-down processing on the input signal. When the input signal voltage slowly drops to around 12V or even lower than 12V, the circuit works in the buck-boost state, the NMOS transistor Q1 and NMOS transistor Q2 are both in working state, and the duty cycle of the two PWM waves is controlled to control the two The respective turn-on time of each NMOS transistor. When the NMOS transistor Q2 is turned on, the inductor L4 converts the electrical energy into magnetic energy and stores it; once the NMOS transistor Q2 is turned off, according to the principle that the current across the inductor L4 cannot undergo abrupt changes, the inductor L4 will convert the stored magnetic energy into electrical energy again and The three output filters C8, C9, and E3 are charged; the boost processing of the input signal can be achieved by reasonably controlling the conduction time of the NMOS transistor Q2. At the same time, resistors R11, R12, and R13 form a sampling circuit for the output signal, which feeds back the sampled signal to the FB pin of the chip LM25118. The LM25118 chip uses an error amplifier to amplify the difference between the sampled output signal and the reference voltage. Further, control the working state of the circuit according to the difference. At the same time, the LM25118 chip is powered by 7V. If the input is directly bucked for power supply, it will cause a large power loss due to a large voltage drop. Therefore, the utility model adopts an output feedback power supply mode. By directly connecting the stable 12V output voltage to the power supply pin of the chip, the voltage drop is reduced, and the stability of the power supply voltage is also improved, which further reduces the system power consumption and improves the system performance.

The PWM wave generation module can instantly adjust the duty cycle of the two PWM waves according to different circuit working states and a certain frequency, and adjust the NMOS in the two circuits of the buck module and the boost module by adjusting the duty cycle. switch state of the tube. It features low noise, high efficiency at full load and can operate in continuous conduction mode.

The switching regulated power supply with an ultra-wide input range utilizes NMOS transistors Q1 and Q2 to switch between cut-off and saturation states. Since the NMOS transistors work in the switching state, they consume no or very little power, thereby reducing power consumption. In general, the conversion efficiency can reach 75% to 95%.

The error acquisition module is used to compare the sampled output signal with a preset reference voltage to generate an error control voltage, and the relationship between the actual output voltage and the target output voltage can be determined by the magnitude and polarity of the error voltage. .

The mode control module adopts the imitation current control mode. By reconstructing the switch tube current signal and comparing it with the error voltage signal, the output signal of the comparator is connected to the PWM wave generation module, and the PWM wave generation module is based on the comparator's output signal. The output voltage judges the working state of the circuit, and adjusts the on-time of the buck module and the boost module respectively by controlling the duty ratio of the output pulse, thereby adjusting the output voltage. The imitation current control mode avoids the leading edge peaks existing in the switching tube current, and the current signal is susceptible to noise interference, etc., and improves the performance of the switching power supply PWM control strategy. The imitation current control mode solves the problem that the duty cycle is too small and the system is unstable by adopting slope compensation, so that the duty cycle of the PWM wave can be less than 5%. The imitation current control mode adds a voltage negative feedback link, the inductor current is no longer an independent variable, so that the switching power supply becomes a first-order unconditional stable system, it only has a single pole and a 90° phase lag, thus It is easy to obtain large open-loop gain and perfect small-signal large-signal characteristics without constraints. The working state of the circuit is adjusted according to the error voltage output by the error acquisition module. When the voltage is high, it works in the buck state, and when the voltage is close to or lower than 12V, it works in the buck-boost state.

It should be understood that the above-mentioned embodiments are only used to describe the present utility model, and are not intended to limit the protection scope of the present utility model patent. Those of ordinary skill in the art, under the inspiration of the present utility model, do not deviate from the protection scope of the present utility model patent. In the following, the embodiments can be replaced or modified, all falling within the protection scope of the present invention.

Claims (8)

1. a kind of switching power supply of ultra-wide input range, which is characterized in that including buck module, boost module, input filter Wave module, output filter module, error acquisition module, mode control module, PWM wave generation module, overheat protector module；

The input filter module, buck module, boost module, output filter module are sequentially connected, the error acquisition module Input terminal and the output end of output filter module connect, the output end of the error acquisition module, overheat protector module with Mode control module connection, the mode control module are also connect with PWM wave generation module, the PWM wave generation module two-way Output is connected respectively to the buck module and boost module and the driving pulse by generating control the buck module, The working condition of boost module.

2. a kind of switching power supply of ultra-wide input range according to claim 1, which is characterized in that the input filter Wave module includes an electrolytic capacitor and a patch capacitor, and the electrolytic capacitor is in parallel with patch capacitor, for defeated to chip Enter foot V_INCarry out decoupling processing.

3. a kind of switching power supply of ultra-wide input range according to claim 2, which is characterized in that the electrolysis electricity Holding is 10 μ F, and the patch capacitor is 100nF.

4. a kind of switching power supply of ultra-wide input range according to claim 1, which is characterized in that the output filter Wave module includes two patch capacitors and a tantalum capacitor, and the patch capacitor and tantalum capacitor are in parallel, for the pressure stabilizing to output Signal is filtered, the further ripple for reducing output voltage.

5. a kind of switching power supply of ultra-wide input range according to claim 4, which is characterized in that the patch electricity Holding is 470nF, and the tantalum capacitor is 68 μ F.

6. a kind of switching power supply of ultra-wide input range according to claim 1, which is characterized in that the buck mould Block uses the SQ4064EY type NMOS tube of vehicle-mounted grade, and the boost module uses the SQ4410EY type NMOS tube of vehicle-mounted grade.

7. a kind of switching power supply of ultra-wide input range according to claim 6, which is characterized in that described The voltage rating of SQ4064EY type NMOS tube is 60V, rated current 12A；The voltage rating of the SQ4410EY type NMOS tube For 30V, rated current 15A.

8. a kind of switching power supply of ultra-wide input range according to claim 1, which is characterized in that the error is adopted Collect the integrated chip that module, mode control module, PWM wave generation module, overheat protector module use model LM25118, institute State 5~40V of change range of input voltage of integrated chip.