US 7,321,245 B2
Pipelined AD converter capable of switching current driving capabilities
Kuniyuki Tani, Gifu (Japan); and Atsushi Wada, Ogaki (Japan)
Assigned to Sanyo Electric Co., Ltd., Osaka (Japan)
Filed on Mar. 25, 2004, as Appl. No. 10/808,575.
Claims priority of application No. 2003-086497 (JP), filed on Mar. 26, 2003; and application No. 2004-060507 (JP), filed on Mar. 04, 2004.
Prior Publication US 2004/0189374 A1, Sep. 30, 2004
Int. Cl. H03K 3/00 (2006.01)
U.S. Cl. 327—109  [327/108; 327/538; 327/543; 323/316] 13 Claims
OG exemplary drawing
 
1. A bias voltage generating circuit comprising:
a driving unit which generates a bias voltage to be applied to a predetermined load, and
a control unit which switches a current driving capability of the driving unit according to a variation in an amount of current required for the load in a period for applying the bias voltage to the load, wherein
the driving unit includes a plurality of bias circuits which are connected in parallel and have different current driving capabilities,
the control unit switches the current driving capability by controlling the number of circuits to operate out of the plurality of bias circuits,
the plurality of bias circuits output the same bias voltage, and
each of the plurality of bias circuits includes:
a CMOS transistor pair composed of a PMOS transistor and an NMOS transistor which are connected in series between a power supply potential and a ground potential and have a common drain connected to their respective gates, the drain outputting the bias voltage;
a first switching element which interrupts a feedthrough current occurring from the CMOS transistor pair; and
a second switching element which controls output of the bias voltage from the CMOS transistor pair.