Abstract The electric power unit of the present invention for a battery-powered electronic appliance comprises a chopper-controlled nonisolated DC-DC converter for converting the output voltage of a battery into required voltage, a bypass switch for bypassing the DC-DC converter, a comparator for comparing the output voltage of the battery with a reference voltage corresponding to the required voltage of the load circuit, and a controller for controlling the bypass switch on the basis of the output signal of the comparator. When the output voltage of the battery is higher than the reference voltage, the battery is connected directly to the load circuit, so that the power of the battery can be supplied to the load circuit without loss due to the operation of the DC-DC converter. When the output voltage is lower than the reference voltage, the output voltage of the battery is converted into a voltage nearly equal to the required voltage of the load circuit by the DC-DC converter, so that substantially all the energy stored in the battery can effectively be used.
An electric power unit for supplying power to a battery-powered load circuit, comprising: a chopper-controlled nonisolated DC-DC converter for converting the output voltage of a battery into a required voltage; a bypass switch for bypassing the chopper-controlled nonisolated DC-DC converter to connect the battery directly to the load circuit; a comparing means for comparing the output voltage of the battery with a threshold voltage to see if the output voltage of the battery is higher than the threshold voltage; and a control means for controlling the bypass switch on the basis of the output signal of the comparing means to hold the chopper-controlled nonisolated DC-DC converter inoperative by closing the bypass switch so that the battery is connected directly to the load circuit and to make the chopper-controlled nonisolated DC-DC converter operative by opening the bypass switch so that the output power of the battery is supplied through the chopper-controlled nonisolated DC-DC converter to the load circuit.
Claim 2
Dependent Claim
157 words
An electric power unit for supplying power to a battery-powered load circuit, comprising: a chopper-controlled nonisolated DC-DC converter for converting the output voltage of a battery into a required voltage; a bypass switch for bypassing the chopper-controlled nonisolated DC-DC converter to connect the battery directly to the load circuit; a comparing means for comparing the output voltage of the battery with a threshold voltage to see if the output voltage of the battery is higher than the threshold voltage; and a control means for controlling the bypass switch on the basis of the output signal of the comparing means to hold the chopper-controlled nonisolated DC-DC converter inoperative by closing the bypass switch so that the battery is connected directly to the load circuit and to make the chopper-controlled nonisolated DC-DC converter operative by opening the bypass switch so that the output power of the battery is supplied through the chopper-controlled nonisolated DC-DC converter to the load circuit.
Claim 3
Dependent Claim
20 words
An electric power unit as claimed in claim 1, wherein said chopper-controlled nonisolated DC-DC converter includes a boosting chopper circuit.
Claim 4
Dependent Claim
17 words
An electric power unit as claimed in claim 1, wherein said bypass switch is a latching relay.
Claim 5
Dependent Claim
39 words
An electric power unit as claimed in claim 1, wherein said comparing means comprises dividing resistors for detecting the output voltage of the battery, and a comparator for comparing the output voltage of the battery with the threshold voltage.