| 摘要 |
PURPOSE:To protect a load from large current flow to be caused by the abnormality of the load and to miniaturize a device by changing reference value which is to be compared to load current value according to an image forming mode. CONSTITUTION:When high voltage generated by a HVT generation circuit 101 is impressed on a HVT load 102, HVT load current flows to a current detecting resistance 103. The reference value is changed by a CPU 106 in response to a selected copying mode. The HVT load current is selected by a multiplexer 105, inputted in a microcomputer 106 and is compared to changed reference value. As a result of comparison, when the HVT load current is bigger than the reference value, the pulse width of a timer counter 109 is changed so that the holding voltage of a condenser C102 becomes zero. Thus, the HVT load current is restricted to specified value. In this constitution, a sequence control circuit and the control circuit of a power source can be integrated onto the same semiconductor tip, thereby miniaturizing the device. |
