| US 7,508,254 B2 | ||
| Reference supply voltage circuit using more than two reference supply voltages | ||
| Yoshiaki Hachiya, Shiga (Japan); Ryutaro Arakawa, Hyogo (Japan); Takashi Kunimatsu, Shiga (Japan); and Minoru Fukui, Osaka (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Filed on Mar. 20, 2007, as Appl. No. 11/723,530. | ||
| Claims priority of application No. 2006-092988 (JP), filed on Mar. 30, 2006. | ||
| Prior Publication US 2007/0229148 A1, Oct. 04, 2007 | ||
| Int. Cl. G05F 1/10 (2006.01) | ||
| U.S. Cl. 327—540 [327/143] | 10 Claims |
| 1. A reference supply voltage circuit for generating a second reference voltage based on a first reference voltage generated
by an electric power supplying circuit, and supplying the second reference voltage to an operation circuit, said reference
supply voltage circuit comprising:
a detecting device for detecting the first reference voltage;
a comparator for outputting a signal which controls an operation state and a stop state of the operation circuit by comparing
the first reference voltage detected by said detecting device with a predetermined reference detection voltage; and
a circuit for preventing any false operation during a pre-operation indefinite time interval
for inputting the first reference voltage,
for maintaining the second reference voltage at a zero voltage when the first reference voltage is lower than a first predetermined
voltage,
for setting the second reference voltage to a voltage equal to the first reference voltage when the first reference voltage
is equal to or higher than the first predetermined voltage and lower than a second predetermined voltage,
for setting the second reference voltage to a voltage proportional to the first reference voltage when the first reference
voltage is equal to or higher than the second predetermined voltage, and
for supplying the second reference voltage to the operation circuit.
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