Title:
SWITCH-TYPE CAPACITOR ELECTRIC-CHARGE PUMP AND SAWTOOTH OSCILLATOR PROVIDED WITH IT
Document Type and Number:
Japanese Patent JPH0661803
Kind Code:
A
Abstract:
PURPOSE: To provide a charge pump with which a buffer stage and a capacitor terminal requiring no negative power voltage are grounded by using a discharging switch which opens and closes in response to the 1st and 2nd value of a periodical binary clock signal to make a capacitor discharging repetitively. CONSTITUTION: While a current switch 24 is supplying a 2nd current I2 to an output terminal 28, a 1st current source 6 charges a capacitor 4 by a 1st current I1. When the voltage of the capacitor 4 becomes equal to the reference voltage Vref of a reference voltage source 16, the switch 24 prevents the current I2 from reaching the terminal 28. Thus, the output generates the charge dQ=I2/I 1.C.Vref (C: capacitance of capacitor 4) in a period of a clock signal CS by means of a current that is turned in to a pulse synchronously with the signal CS. The source 16 is hardly set in a load state by a comparator 12 and requires no buffer stage. Furthermore, a 2nd capacitor terminal 8 can be grounded and the switch 24 can have a current path that requires no negative power voltage against the ground.
Inventors:
SCHOOFS FRANCISCUS A C M (NL)
Application Number:
JP14227093A
Publication Date:
March 04, 1994
Filing Date:
June 14, 1993
Export Citation:
Assignee:
KONINKL PHILIPS ELECTRONICS NV (NL)
International Classes:
H03H19/00; H03K4/50; H03K4/501; (IPC1-7): H03K4/50; H03H19/00
Attorney, Agent or Firm:
Akihide Sugimura (5 outside)
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