| 摘要 |
PURPOSE:To minimize the heat planning of a power source circuit, by performing the control of load while monitoring a primary side current increasing with heavy load by a current detection circuit. CONSTITUTION:When a primary side current I1 increases, the voltage between both terminals of the current detection resistor R1 of a current detection circuit 1 also becomes high and, when the value of said voltage reaches a certain value, a transistor Q1 is turned ON and a transistor Q2 is also turned ON. The collector current I0 of the transistor Q2 charges the resistor R2 and capacitor C1 of an integrating circuit for monitoring a time. The voltage between both terminals of said capacitor C1 appears in a secondary side resistor R3 through a photocoupler 2. MPU3 monitors the voltage between both terminals of the resistor R3 through an analogue port AP to make it possible to know the state of the primary side current I1 and control secondary side load 4 on the basis of the voltage level thereof. |
