Charging device, electronic equipment including same, and control method of charging device

摘要

A charging device to charge a secondary battery that includes a DC/DC circuit to generate a charging current supplied to the secondary battery, an impedance measurement circuit to measure an impedance of the secondary battery, a first control circuit to output a duty-cycle decrease signal in accordance with the measured impedance, a charging-current monitor circuit to detect the charging current outputted from the DC/DC circuit when the duty cycle of the pulses generated by the DC/DC circuit is decreased by the duty-cycle decrease signal, and, a second control circuit to compare the charging current detected by the charging-current monitor circuit and a charging-current threshold and to output to the DC/DC circuit a frequency change signal that increases a switching operation frequency in the DC/DC circuit.

主权项

1. A charging device to charge a secondary battery, the charging device comprising:
a DC/DC circuit to generate a charging current supplied to the secondary battery; an impedance measurement circuit to measure an impedance of the secondary battery; a first control circuit to output a duty-cycle decrease signal in accordance with the measured impedance: a charging-current monitor circuit to detect the charging current outputted from the DC/DC circuit when the duty cycle of the pulses generated by the DC/DC circuit is decreased by the duty-cycle decrease signal; and a second control circuit to compare the charging current detected by the charging-current monitor circuit and a charging-current threshold and to output to the DC/DC circuit a frequency change signal that increases a switching operation frequency in the DC/DC circuit, wherein the second control circuit determines from the comparison of the charging current detected by the charging-current monitor circuit and a charging-current threshold that the power supply for the secondary battery has decreased and in response outputs a frequency change signal to the DC/DC circuit to cause the switching operation frequency in the DC/DC circuit to change.