PWM buck convertor with overcurrent protection function

An overcurrent protection and converter technology, applied in output power conversion devices, conversion equipment without intermediate conversion to AC, electrical components, etc. Power consumption, ensure normal work, and ensure the effect of stability

Inactive Publication Date: 2009-12-02
SHENZHEN CHIP HOPE MICRO ELECTRONICS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is that in the PWM type step-down converter of the prior art, a large amount of heat will be generated when a large current flows through the power tube and the inductor

Method used

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  • PWM buck convertor with overcurrent protection function
  • PWM buck convertor with overcurrent protection function
  • PWM buck convertor with overcurrent protection function

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Embodiment Construction

[0030] Such as figure 1 As shown, in the PWM-type step-down converter with overcurrent protection function of the present invention, it mainly includes a control circuit, a first switch tube 101 connected between the input power supply Vin and the inductor LX112, and related peripheral circuits. The relevant peripheral circuit has a freewheeling diode 111, a filter capacitor 113, a load resistor 114, and a first feedback voltage dividing resistor 115 and a second feedback voltage dividing resistor 116, wherein the first feedback voltage dividing resistor 115 and the second feedback voltage dividing resistor 115 The connection node of 116 outputs the system feedback voltage; the invention of this technical solution is that a current limiting circuit is set in the PWM type step-down converter, which is used to sample the current signal on the first switching tube 101 and output the overcurrent signal, and the control circuit judges Whether the overcurrent signal is greater than ...

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Abstract

The invention relates to a PWM buck convertor with overcurrent protection function, which comprises a control circuit, a first switching tube connected between an input power source and an inductor, and a current-limit circuit, wherein the current-limit circuit is used for sampling current signals on the first switching tube and outputting overcurrent signals; the control circuit judges whether the overcurrent signals are greater than a preset current maximum to control the connection and cut off of the first switching tube; and the PWM buck convertor is provided with the current-limit circuit, so that a power tube is cut off when the current is increased to the preset current maximum to protect a chip and ensure the normal work of a switch power supply. Furthermore, a capacitor in an RC circuit outputs sampling voltage so as to avoid the influence of power supply voltage vibration on the current-limit circuit in the direct sampling process; when the overcurrent happens, the cut-off time of the power tube is fixed so as to avoid the repeat starting of the power tube in short time and reduce power consumption; and two shifts of cut-off time are automatically selected according to the output voltage of the buck convertor so as to ensure the stability of the output voltage.

Description

technical field [0001] The present invention relates to PWM type step-down conversion, more specifically, relates to a PWM type step-down converter with overcurrent protection function. Background technique [0002] With the continuous pursuit of energy saving and environmental protection worldwide, switching power supply circuits, as an important development direction of microelectronics technology, are getting more and more attention. Especially in the fields of automotive electronics, industrial control, LED lighting, etc., step-down switching power supply circuits are widely used due to their high conversion efficiency and play an important role. Step-down switching power supply circuit can convert DC high voltage into DC constant low power supply or constant current to supply power to the load. In addition to the performance to meet the requirements of power supply products, the protection measures of the switching power supply itself are also very important. Overcurr...

Claims

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Application Information

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IPC IPC(8): H02M1/32H02M3/07
Inventor 陈志军范文锴张波
Owner SHENZHEN CHIP HOPE MICRO ELECTRONICS LTD
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