Constant-voltage switching power supply circuit with flyback diode voltage compensation

Abstract

The invention provides a constant-voltage switching power supply circuit with flyback diode voltage compensation. The constant-voltage switching power supply circuit comprises a flyback diode voltagecompensation module, an input voltage source, a load, a power tube, a flyback diode, an inductor, an output capacitor, a sampling diode, a first divided resistor, a second divided resistor, a samplingcapacitor, an error amplifier, a control and drive module and a second reference voltage source, wherein the flyback diode voltage compensation module comprises a first adder, a second adder and a flyback diode voltage sampling circuit, and the sampling circuit comprises a negative feedback resistor, an NMOS transistor, an energy storage capacitor, a first reference voltage source and a samplingamplifier. According to the constant-voltage switching power supply circuit provided by the invention, the input signal of the error amplifier is compensated by detecting the voltage difference between the anode and the cathode of the flyback diode, and even if the voltage of the flyback diode changes along with the load current, the output voltage does not change along with the load current, so that the stability of the output voltage is improved.

Description

technical field [0001] The invention relates to the field of integrated circuit design and application, in particular to a constant-voltage switching power supply circuit with freewheeling diode voltage compensation. Background technique [0002] In recent years, the application of constant voltage switching power supply circuits has become increasingly widespread, and it can be used in power management such as battery charging. With the popularity of portable devices such as mobile phones, related research and development have also attracted the attention of the industry. [0003] At present, in the existing constant voltage switching power supply circuit, its output voltage is a set value. In an ideal state, the output voltage value should not change with the change of the application environment. For example, in a prior art solution, a constant voltage switching power supply circuit is formed by power tubes, inductors, freewheeling diodes and output capacitors, and the o...

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Problems solved by technology

[0006] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a constant voltage switching power supply circuit with freewheeling diode voltage compensation, which is used to solve the problem of poor output voltage stability of the constant voltage switching power supply circuit in the prior art

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