CHARGING CONTROL CIRCUIT OF BATTERY FOR VEHICLE

摘要

PURPOSE: A charging control circuit of a battery for a vehicle is provided to control the voltage of a generator by operating a battery charging voltage detector continuously without operating a load-responding characteristic circuit even though engine RPM(Revolution Per minute) falls lower than set RPM in a moment when the generator outputs the maximum voltage. CONSTITUTION: A charging control circuit of a battery for a vehicle is comprised of: a battery charged-voltage detector(10) for detecting the charged voltage of a battery; an enable control unit(12) controlling the detector to be operated normally by generating an enable signal if the charged voltage of the battery is higher than the minimum reference voltage or engine RPM is higher than set RPM; a load-responding characteristic circuit(14) outputting voltage increased at a predetermined rate from the detected voltage if the enable control unit does not output an enable signal; a sawtooth wave oscillator(16) generating sawtooth waves; a generator drive unit(18) controlling the generated voltage of a generated by comparing the sawtooth waves with the output signal of the detector or the characteristic circuit; and a hysteresis circuit(20) raising or falling RPM reference voltage for detecting engine RPM depending on whether the enable control unit detects the battery charged voltage lower or higher than the minimum reference voltage. The RPM reference voltage is dropped when the generator outputs the maximum voltage by an instantaneous overload of the battery. Therefore, the generator voltage is controlled depending on the output voltage of the detector even though the engine RPM falls lower than the set RPM.