Title:
CAPACITIVE LOAD DRIVING CIRCUIT
Document Type and Number:
Japanese Patent JP3511168
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To make the voltage of a capacitive load at the time of converting the polarity of charge voltage to be changed smoothly without lowering the values of the charge voltage.
SOLUTION: When a switch S5 is closed at the time of discharging the positive charge stored on a capacitive load C, the voltage of the capacitive load C is higher than reference voltage +V1, +V2. Hence the outputs of comparators CMP3, CMP4 become both L levels, transistors MP1, MP2 are both turned ON, the drain currents of respective transistors become the base current of a transistor Q2, a large collector current is made to flow through the transistor Q2 and, then, the load C is discharge. When the the voltage of the load C decreases than the reference voltage +V1 in accordance with the reduction of the voltage of the load C, the output of the comparator CMP3 is inverted from the L level to an H level, the transistor MP1 becomes from an ON state to an OFF state, the base current of the transistor Q2 decrease and then the charge of the load C is discharged in accordance with the decreased base current.
Inventors:
Suzuki, Ryoichi
Kawamoto, Koji
Kawauchi, Norihiro
Tanaka, Takashi
Kawamoto, Koji
Kawauchi, Norihiro
Tanaka, Takashi
Application Number:
JP2000048542A
Publication Date:
March 29, 2004
Filing Date:
February 25, 2000
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G02F1/133; G09G3/20; G09G3/296; G09G3/30; G09G3/36; (IPC1-7): G09G3/20; G02F1/133; G09G3/28; G09G3/30; G09G3/36
Attorney, Agent or Firm:
吉岡 宏嗣
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