Current-stabilizing switch power source with voltage ripple detection circuit

Abstract

The invention provides a current regulation power supply relating to electric technique field. The power supply output current dc amount is detected by a voltage ripple detecting circuit and fed back to a control circuit to control the turn-on and turn-off of the power switch tube thus to realize regulated output. The voltage ripple detecting circuit of the current regulation switch power supply provided by this invention comprises a high pass filtering module, a second order differentiation operation module, a linear operation module, and a clock gating / signal memory module which are connected in series sequentially. The voltage ripple of the current regulation switch power supply output voltage is firstly extrated and then performed by second order differentiation, linear operation and memory extension to 'resume' the dc output voltage of the current regulation switch power supply which is finally fed back to PWM, PFM or PSM control ciucuit so as to realize regulated output via adjusting the turn-on and turn-off of the power switch tube by the control circuit. The present invention has higher power efficiency and lower circuit cost as well as smaller power supply volume compared with prior current regulation switch power supply.

Description

technical field [0001] The invention belongs to the field of electronic technology, and relates to a steady-current switching power supply, in particular to a detection and control technology for the output voltage of the voltage-stabilizing switching power supply. Background technique [0002] The basic working principle of the switching power supply is that in the case of input voltage changes, internal parameters changes, and external load changes, the control system detects the controlled output current signal and feeds the signal back to the PWM, PFM or PSM control mode for closed-loop control. Feedback, adjust the turn-on and turn-off time of the power switching device of the main circuit, so that the output current of the switching power supply is stable. [0003] Fig. 1 is an existing AC / DC steady current switching power supply with transformer isolation. In the input stage of the main circuit, VAC is the AC input voltage, typically 220V, and Vin is the line input v...

AI Technical Summary

Problems solved by technology

[0004] The disadvantages of commonly used steady-current switching power supply systems are: 1. The output current detection circuit needs to consume extra power, resulting in a decrease in power supply efficiency; 2. In AC / DC converters, the input circuit and output circuit are generally separated by an optocoupler. In order to ensure the safety of users' electricity use, other components that provide DC isolation such as optocouplers increase the cost and volume of the system, and the power consumption of optocouplers also reduces power efficiency

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