Power source device
View Patent ↗A power source device is provided including a boosting circuit for stepping-up an input voltage to a desired output voltage, a starter circuit for starting the boosting circuit in a starting period thereof, and a drive circuit for driving the boosting circuit as a substitute for the starter circuit after the output voltage of the boosting circuit becomes equal to or greater than a predetermined level. The starter circuit comprises a starter signal generation circuit for generating a starter signal which on/off controls a MOS transistor used for stepping-up in the boosting circuit, and a determining/controlling circuit which detects whether or not a monitor voltage in the boosting circuit is equal to or greater than a predetermined level while the MOS transistor is in the on-state, and inhibits outputting if the starter signal if the monitor voltage is equal to or greater than the predetermined level.
1. A power source device comprising:
a boosting circuit for stepping-up an input voltage to a desired output voltage;
a starter circuit for starting the boosting circuit in a starting period of the boosting circuit;
a drive circuit for driving the boosting circuit as a substitute for the starter circuit;
a voltage source for providing an input voltage to the boosting circuit and the starter circuit; and
a switching element associated with the boosting circuit for switching from the boosting circuit to the drive circuit when the output voltage of the boosting circuit reaches a predetermined level;
wherein the starter circuit is arranged to on/off control the switching element when a predetermined monitor voltage generated in the boosting circuit reaches a predetermined level.
2. A power source device comprising:
a boosting circuit for stepping-up an input voltage to a desired output voltage;
a starter circuit for starting the boosting circuit in a starting period of the boosting circuit; and
a drive circuit for driving the boosting circuit as a substitute for the starter circuit;
a switching element associated with the boosting circuit for switching from the starter circuit to the drive circuit when the output voltage of the boosting circuit reaches a predetermined level;
wherein the starter circuit includes:
a starter signal generator which generates a starter signal for on/off controlling the switching element; and
a determining/controlling circuit which determines if a monitor voltage generated in the boosting circuit reaches a predetermined level; and
wherein when the monitor voltage reaches the predetermined level, the determining/controlling circuit provides an output signal to the starter signal generator circuit which provides an output signal to the switching element to change from the boosting circuit to the drive circuit.
3. The power source device according to claim 2 , wherein the starter signal generator comprises two constant current circuits and two capacitors alternately charged by respective constant current circuits, and a frequency of the starter signal is arranged to be controlled by altering constant current values of both constant current circuits, and a duty ratio of the starter signal is arranged to be controlled by altering capacitances of both capacitors.