A switching power supply and a circuit for increasing its output current adjustment rate

A technology of output current and switching power supply, which is applied in the field of switching power supply and its internal circuit, can solve the problems of low precision and small range of applicable parameters, and achieve the effects of high precision, wide range of adaptable parameters, and improved adjustment rate

CN103390992BActive Publication Date: 2015-09-30CRM ICBG (WUXI) CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2015-09-30

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Abstract

The invention provides a switching power supply and a circuit improving an output current regulation factor of the switching power supply. The circuit improving the output current regulation factor of the switching power supply comprises a voltage amplifier, a first voltage comparator, a first RS trigger, a pulse generation circuit, a second voltage comparator, a counter and a voltage regulator, wherein the voltage amplifier is used for carrying out pre-amplification on sampling voltage, a first input end of the first voltage comparator is connected with the output end of the voltage amplifier, a second input end of the first voltage comparator is connected with the output end of the voltage regulator, the set input end of the first RS trigger is used for receiving an external clock signal, the reset input end of the first RS trigger is connected with the output end of the first voltage comparator, the output end of the first RS trigger generates a switch control signal, the pulse generation circuit generates a reset pulse signal and a counting pulse signal, the second voltage comparator generates a direction control signal, the counter uses the counting pulse signal as a clock, and carries out progressive increase counting or progressive decrease counting according to the reset pulse signal and the direction control signal, and the voltage regulator regulates output internal reference voltage according to counting values output by the counter. The switching power supply and the circuit improving the output current regulation factor of the switching power supply are large in range of applicable parameters, and high in accuracy, and have the obvious advantage of improving the output current line regulation factor.
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Description

technical field

[0001] The invention relates to a switching power supply and its internal circuit, in particular to a switching power supply and a circuit for improving its output current adjustment rate. Background technique

[0002] Switching power supply has the characteristics of high efficiency and small size, and is the preferred power supply solution for electronic equipment, especially mobile electronic equipment. For offline switching power supplies, it is usually required that the power supply has constant voltage / constant current output characteristics, that is, it can provide a constant output voltage before the load current reaches the limited current, and when the load voltage reaches a constant current, the power supply works in constant current mode and outputs a constant current.

[0003] The flyback power supply can adjust the output voltage and current by detecting the voltage information of the transformer winding to meet the requirements of constant volt...

Examples

Embodiment Construction

[0072] The present invention will be further described below in conjunction with specific embodiments and accompanying drawings, but the protection scope of the present invention should not be limited thereby.

[0073] Figure 5 The circuit diagram of the switching power supply of this embodiment is shown, and those skilled in the art should understand that, Figure 5 The circuit 50 for improving the line regulation rate of the output current of the switching power supply and other components directly related to it are mainly shown in the figure, and the complete circuit is not shown. Those skilled in the art should be able to know the complete circuit of the switching power supply in combination with known peripheral circuits .

[0074] refer to Figure 5 , the switching power supply includes a transformer 502, a switch 501 connected in series with the primary coil of the transformer 502, and a sampling resistor 503 connected in series with the switch 501. The sampling resi...