Negative Current Clocking

摘要

A switching mode power supply (SMPS) is capable of clearing an overvoltage condition. The overvoltage is determined by detecting that the output voltage has exceeded the input voltage by a limited amount. The overvoltage is cleared by repetitively turning on and then off the switches controlling the flow of energy to the SMPS in sequence until the excess charge resulting from the overvoltage is couple to circuit ground, and the output is reduced to within acceptable limits.

主权项

1. A power supply, comprising:
a) a switching mode power supply (SMPS) capable of receiving a target input voltage and capable of providing a current to a load at an output voltage equivalent to said input voltage; b) a first switch capable of being activated when said output voltage falls below said input voltage; c) a second switch capable of being activated to reduce an overvoltage; wherein said overvoltage is capable of being reduced to within allowable limits by cycling the second switch followed by the first switch a number of times until output voltage of the SMPS is within an upper limit of the target input voltage d) an active diode block capable of turning off the second switch when current flow through the second switch drops to zero; and e) wherein said SMPS is capable of receiving said output voltage fed back to an input of said SMPS and combining with said target input voltage to control the first and second switch when operating in pulse frequency modulation (PFM) mode.