Abstract:
A charging circuit for a secondary battery includes a constant-voltage circuit part outputting one of a plurality of predetermined constant voltages and charges the secondary battery by applying the constant voltage thereto, a detection circuit part detecting a battery voltage of the secondary battery, and a control circuit part controlling the selection of the constant-voltage in response to the detected battery voltage. Another charging circuit includes a constant-current circuit part outputting, to the secondary battery, one of two predetermined constant currents, a constant-voltage circuit part charging the secondary battery by applying a predetermined constant voltage thereto, a battery voltage detection circuit part detecting a battery voltage of the secondary battery, a charge current detection circuit part outputting a predetermined charge completion signal, and a charge control circuit part stopping operations of the constant-current circuit part and constant-voltage circuit part when receiving the charge completion signal.
Abstract:
This patent specification describes a DC-DC converter which includes a switch configured to control an output voltage, a driver circuit configured to drive the switch, a flip-flop configured to control the driver circuit, an error amplifier configured to compare a feedback voltage of the output voltage with a reference voltage, a detector configured to sense an output current, a control voltage generator configured to generate a control voltage being ramped and a PWM comparator configured to compare the control voltage with an output voltage of the error amplifier and output a reset signal to the flip-flop. Ramping speed of the control voltage is changed in accordance with an external-control voltage input at an external-control terminal.
Abstract:
This patent specification describes a boost circuit which includes an inductor wired to an input terminal, a switching device connected between the inductor and a ground, a rectifying device formed of a MOS transistor and connected between the inductor and an output terminal and configured to be switched in accordance with the control signal, a first transistor wired to the input terminal and to a substrate gate of the rectifying device, a second transistor wired to the substrate gate of the rectifying device and to the output terminal and a controller configured to control each operation of the switching device, the rectifying device and the first and second transistors so that the first transistor is off and the second transistor is on in a boost mode and the first transistor is on and the second transistor is off in a boost suspend mode.
Abstract:
A battery charging apparatus includes a voltage detecting circuit, a current detecting circuit, a charging circuit, and a charge control circuit. The voltage detecting circuit detects a battery voltage of the battery and accordingly outputs a signal. The current detecting circuit detects a battery current supplied to the battery and accordingly outputs a signal. The charging circuit executes a current supply control to perform the charging to the battery such that the battery voltage becomes equal to a voltage predetermined based on control signals and also that the charging current becomes equal to a current predetermined based on the control signals. The charge control circuit instructs the charging circuit with the control signals to set the battery voltage and the charge current in response to a voltage indicated by the signal from the voltage detecting circuit.