BOOST switching power supply circuit applied to high step-up ratio

Abstract

The invention relates to the technical field of switching power supply circuits, in particular to a BOOST switching power supply circuit applied to a high step-up ratio. The BOOST switching power supply circuit applied to the high step-up ratio comprises an input filtering module, a first-stage step-up module, a second-stage step-up module and a control module, the input filtering module comprises an input capacitor Cin and is used for filtering an input voltage Vin; the first-stage boost module comprises a boost inductor L1, a switch tube MOS Q2, a rectifier diode D1 and an output capacitor Co1. The boost circuit is composed of an input capacitor Cin, a boost inductor L1, a switch tube MOS Q1, a switch tube MOS Q2, boost rectifier diodes D1 and D2, output capacitors Co1 and Co2 and a control chip U1, one chip is used for controlling a two-stage BOOST boost circuit, control is simple, the number of parts is small, large-current output and high-step-up-ratio boost can be achieved, and in a power supply circuit using a low-voltage battery or a solar rechargeable battery product, the boost circuit can be applied to a power supply circuit. And the use value is high.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supply circuits, in particular to a BOOST switching power supply circuit applied to a high voltage step-up ratio. Background Art

[0002] In the Boost circuit, the output voltage Vo is given by the formula Decision, among which is the output voltage, is the input voltage, is the PWM duty cycle. This formula shows that, theoretically, the input voltage can be boosted to any multiple. However, in practical applications, due to line and device losses, the duty cycle typically does not exceed 0.9. Therefore, from an engineering perspective, the maximum duty cycle of a boost circuit is approximately 10. For example, with a battery-powered 1.5V input, the maximum output is approximately 15V, resulting in a step-up ratio of approximately 10. However, if a 1.5V input is required and a voltage above 15V is required, achieving this becomes difficult.

[0003] With the increasing use of solar energy, rechargeable batteries are increasingly being used to power devices such as solar lighting and solar monitoring equipment. Public lighting systems are required to have 1 / 10 emergency lighting for emergency use during power outages. These devices are often powered by rechargeable batteries, with voltages typically ranging from 1.2 to 6.4V. Current solutions for achieving a 10x voltage step-up ratio: 1. Use two independent BOOST circuits in series to boost the voltage to less than 100 times; 2. Use transformer turns ratio conversion to boost the voltage to more than 100 times.

[0004] Using two independent BOOST circuits in series, however, complicates control, doubles the number of parts, and increases costs. Using a transformer turns ratio-based boost solution also requires more parts, is more expensive, and has low efficiency. Therefore, this patented two-stage boost solution, using a single control IC, can boost the voltage by approximately 100 times while effectively reducing costs and improving efficiency. The circuit is also relatively simplified, making it highly valuable. Summary of the Invention

[0005] The object of the present invention is to provide a BOOST switching power supply circuit for high step-up ratio, so as to solve the problems proposed in the above background art of using two independent BOOST boost circuits in series, which has complex control, doubled number of parts and high cost, and using a transformer turns ratio conversion boost solution, which has a large number of parts, high cost and low efficiency.

[0006] To achieve the above object, the present invention provides a BOOST switching power supply circuit for high voltage step-up ratio, comprising:

[0007] Input filter module, first stage boost module, second stage boost module and control module;

[0008] The input filter module includes an input capacitor Cin, which is used to filter the input voltage Vin;

[0009] The first-stage boost module includes a boost inductor L1, a switch tube MOS Q2, a rectifier diode D1 and an output capacitor Co1;

[0010] One end of the boost inductor L1 is connected to the positive electrode of the input capacitor Cin, and the other end is connected to the drain of the switch tube MOS Q2 and the positive electrode of the rectifier diode D1;

[0011] The source of the switch tube MOS Q2 is grounded, and the gate is connected to the output end of the control module;

[0012] The cathode of the rectifier diode D1 is connected to the anode of the output capacitor Co1 and the input end of the second-stage boost module;

[0013] The second-stage boost module includes a boost inductor L2, a switch tube MOS Q1, a rectifier diode D2 and an output capacitor CO2;

[0014] One end of the boost inductor L2 is connected to the cathode of the rectifier diode D1, and the other end is connected to the drain of the switch tube Q1 and the anode of the rectifier diode D2;

[0015] The source of the switch tube MOS Q1 is grounded, and the gate is connected to the output end of the control module;

[0016] The cathode of the rectifier diode D2 is connected to the anode of the output capacitor Co2, serving as the boosted voltage output terminal Vo+;

[0017] The control module includes a control chip U1, which is used to generate a PWM signal to control the on and off of the switch tube MOS Q1 and the switch tube MOS Q2 to achieve two-stage boost.

[0018] As a further improvement of the present technical solution, the control chip U1 is a dedicated power control chip or MCU, and its PWM output terminals are respectively connected to the gates of the switch tubes MOS Q1 and MOS Q2.

[0019] As a further improvement of the present technical solution, the switch tube MOS Q1 and the switch tube MOS Q2 are any one of MOSFET, triode or thyristor.

[0020] As a further improvement of the present technical solution, the working state of the first-stage boost module and the second-stage boost module is a continuous conduction mode, and the total boost satisfies the following formula:

[0021]

[0022] in, and are the duty cycles of the first and second stage boost respectively.

[0023] As a further improvement of the present technical solution, the output capacitors Co1 and Co2 are electrolytic capacitors or thin film capacitors, which are used to stabilize the output voltage.

[0024] As a further improvement of the present technical solution, the input voltage range of the switching power supply circuit is 1.2V to 6.4V, and the output voltage is 100 times the input voltage.

[0025] As a further improvement of the present technical solution, the switching power supply circuit is applied to emergency lighting equipment or monitoring equipment powered by solar rechargeable batteries.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This device is used in BOOST switching power supply circuits with high step-up ratios. It consists of input capacitor Cin, boost inductor L1, switch tubes MOS Q1 and MOS Q2, boost rectifier diodes D1 and D2, output capacitors Co1 and Co2, and control chip U1. One chip is used to control two-stage BOOST boost circuits. The control is simple, with fewer parts, and can achieve large current output and high step-up ratio boost. It has great use value in power supply circuits using low-voltage batteries or solar rechargeable batteries.

[0028] 2. In the BOOST switching power supply circuit with high boost ratio, the input voltage Vin is filtered by the input capacitor Cin and then connected to the first-stage boost module. The control chip U1 outputs a PWM signal to control the on and off of the switch tube MOS Q2, so that the boost inductor L1 stores and releases energy periodically, and charges the output capacitor Co1 through the rectifier diode D1 to complete the first-stage boost. The output voltage of Co1 serves as the input of the second-stage boost module. By controlling the on and off of the switch tube MOS Q1, the boost inductor L2 stores and releases energy again, and charges the output capacitor Co2 through the rectifier diode D2, finally achieving a two-stage boost. By adjusting the PWM duty cycle and , the total boost ratio can be flexibly controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure is a schematic diagram of the circuit structure of a BOOST switching power supply circuit applied to a high voltage step-up ratio according to the present invention. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] In a specific embodiment, Figure 1 The figure shows a BOOST switching power supply circuit for a high step-up ratio. The switching power supply circuit has an input voltage range of 1.2V to 6.4V and an output voltage 100 times the input voltage. The switching power supply circuit is used in emergency lighting equipment or monitoring equipment powered by solar rechargeable batteries. The switching power supply circuit includes an input filter module, a first-stage boost module, a second-stage boost module, and a control module.

[0032] The input filter module includes an input capacitor Cin, which is used to filter the input voltage Vin, reduce the fluctuation of the input voltage, and improve the stability of the subsequent boost module.

[0033] The first-stage boost module includes a boost inductor L1, a switch tube MOS Q2, a rectifier diode D1 and an output capacitor Co1. Through the first-stage boost, the input voltage is increased to an intermediate voltage level to prepare for the subsequent second-stage boost.

[0034] One end of the boost inductor L1 is connected to the positive electrode of the input capacitor Cin, and the other end is connected to the drain of the switch tube MOS Q2 and the positive electrode of the rectifier diode D1.

[0035] The source of the switch tube MOS Q2 is grounded, and the gate is connected to the output end of the control module.

[0036] The cathode of the rectifier diode D1 is connected to the anode of the output capacitor Co1 and the input end of the second-stage boost module.

[0037] The second-stage boost module includes a boost inductor L2, a MOS switch Q1, a rectifier diode D2, and an output capacitor CO2. Output capacitors Co1 and Co2 are electrolytic or film capacitors used to stabilize the output voltage. This two-stage boost achieves a high boost ratio, while the boost ratio per stage is relatively low, facilitating component selection and improving efficiency.

[0038] One end of the boost inductor L2 is connected to the cathode of the rectifier diode D1 , and the other end is connected to the drain of the switch tube Q1 and the anode of the rectifier diode D2 .

[0039] The first-stage boost module and the second-stage boost module operate in continuous conduction mode. By adopting continuous conduction mode in both stages of the boost module, the switching loss is reduced and the overall efficiency is improved. The total boost satisfies the following formula:

[0040]

[0041] in, and are the duty cycles of the first and second stage boost respectively.

[0042] The source of the switch tube MOS Q1 is grounded, and the gate is connected to the output end of the control module.

[0043] The cathode of the rectifier diode D2 is connected to the anode of the output capacitor Co2, serving as the boosted voltage output terminal Vo+.

[0044] The control module includes a control chip U1, which is used to generate PWM signals to control the on and off of the switch tubes MOS Q1 and MOS Q2 to achieve two-stage boost. Using a single control chip U1 can achieve the control of two-stage boost, which simplifies the circuit structure and reduces costs. At the same time, by adjusting the duty cycle of the PWM signal, the boost ratio can be flexibly controlled to meet different application requirements. At the same time, the control chip U1 is a dedicated power supply control chip or MCU, and its PWM output terminal is respectively connected to the gate of the switch tube MOS Q1 and the switch tube MOS Q2. The switch tube MOS Q1 and the switch tube MOS Q2 are any one of MOSFET, triode or thyristor.

[0045] In the specific application process, combined with Figure 1 The input voltage Vin is filtered by the input capacitor Cin and then connected to the first-stage boost module. The control chip U1 outputs a PWM signal to control the on and off of the switch tube MOS Q2, so that the boost inductor L1 stores and releases energy periodically, and charges the output capacitor Co1 through the rectifier diode D1, completing the first-stage boost. The output voltage of Co1 serves as the input of the second-stage boost module. By controlling the on and off of the switch tube MOS Q1, the boost inductor L2 stores and releases energy again, and charges the output capacitor Co2 through the rectifier diode D2, finally achieving a two-stage boost. By adjusting the PWM duty cycle and , the total boost ratio can be flexibly controlled.

[0046] Taking the input voltage of 1.5V as an example, set the duty cycle =0.9, =0.9, the total boost ratio is calculated according to the formula: , thus achieving a 100-fold boost effect.

[0047] The present invention achieves a 100-fold boost ratio through two-stage coordinated boosting, meeting the need to boost a low-voltage battery (e.g., 1.5V) to 150V. It also uses a single control chip to drive two-stage switching tubes, reducing the number of components and lowering costs. It also uses a continuous conduction mode to reduce switching losses and improve overall efficiency. This makes it well-suited for scenarios such as emergency lighting and monitoring equipment powered by solar rechargeable batteries.

[0048] The present invention is composed of an input capacitor Cin, a boost inductor L1, switch tubes MOS Q1 and MOS Q2, boost rectifier diodes D1 and D2, output capacitors Co1 and Co2, and a control chip U1. A single chip is used to control a two-stage BOOST boost circuit, which has simple control and fewer parts. It can achieve large current output and high boost ratio boost, and has great use value in power supply circuits using low-voltage batteries or solar rechargeable battery products.

[0049] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A BOOST switching power supply circuit for high voltage step-up ratio, characterized in that: include: Input filter module, first stage boost module, second stage boost module and control module; The input filter module includes an input capacitor Cin, which is used to filter the input voltage Vin; The first-stage boost module includes a boost inductor L1, a switch tube MOS Q2, a rectifier diode D1 and an output capacitor Co1; One end of the boost inductor L1 is connected to the positive electrode of the input capacitor Cin, and the other end is connected to the drain of the switch tube MOS Q2 and the positive electrode of the rectifier diode D1; The source of the switch tube MOS Q2 is grounded, and the gate is connected to the output end of the control module; The cathode of the rectifier diode D1 is connected to the anode of the output capacitor Co1 and the input end of the second-stage boost module; The second-stage boost module includes a boost inductor L2, a switch tube MOS Q1, a rectifier diode D2 and an output capacitor CO2; One end of the boost inductor L2 is connected to the cathode of the rectifier diode D1, and the other end is connected to the drain of the switch tube Q1 and the anode of the rectifier diode D2; The source of the switch tube MOS Q1 is grounded, and the gate is connected to the output end of the control module; The cathode of the rectifier diode D2 is connected to the anode of the output capacitor Co2, serving as the boosted voltage output terminal Vo+; The control module includes a control chip U1, which is used to generate a PWM signal to control the on and off of the switch tube MOS Q1 and the switch tube MOS Q2 to achieve two-stage boost.

2. A BOOST switching power supply circuit for high voltage step-up ratio according to claim 1, characterized in that: The control chip U1 is a dedicated power control chip or MCU, and its PWM output terminals are connected to the gates of the switch tubes MOS Q1 and MOS Q2 respectively.

3. The BOOST switching power supply circuit for high voltage step-up ratio according to claim 1, characterized in that: The switch tube MOS Q1 and the switch tube MOS Q2 are any one of MOSFET, triode or thyristor.

4. The BOOST switching power supply circuit for high voltage step-up ratio according to claim 1, characterized in that: The first-stage boost module and the second-stage boost module operate in continuous conduction mode, and the total boost satisfies the following formula: ； Among them, D1 and D2 are the duty cycles of the first and second stage boost respectively.

5. The BOOST switching power supply circuit for high voltage step-up ratio according to claim 1, characterized in that: The output capacitors Co1 and Co2 are electrolytic capacitors or film capacitors, and are used to stabilize the output voltage.

6. The BOOST switching power supply circuit for high voltage step-up ratio according to claim 1, characterized in that: The input voltage range of the switching power supply circuit is 1.2V to 6.4V, and the output voltage is 100 times the input voltage.

7. The BOOST switching power supply circuit for high voltage step-up ratio according to claim 1, characterized in that: The switching power supply circuit is applied to emergency lighting equipment or monitoring equipment powered by solar charging batteries.

Images