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Title:
CONTROL VOLTAGE GENERATING CIRCUIT, PLL CIRCUIT PROVIDED WITH IT AND CD-ROM DRIVER PROVIDED WITH IT
Document Type and Number:
Japanese Patent JP2933134
Kind Code:
B2
Abstract:

PROBLEM TO BE SOLVED: To build in an LSI by decreasing a capacitance of a primary capacitor being a component of a loop filter without changing a characteristic of the circuit.
SOLUTION: A main current control section 50 supplies/receives a main control current Ir in response to an increase instruction signal UP# and a decrease instruction signal DN from a phase comparator 40. An auxiliary current control section 60 supplies/receives an auxiliary control current Ic that is smaller than the main control current Ir in response to the increase instruction signal UP# and the decrease instruction signal DN. A loop filter 70 is provided with a primary side capacitor C0 that supplies/receives the auxiliary control current Ic to generate a primary voltage based on the main control current Ir and the auxiliary control current Ic, a voltage current converter 71 that converts a primary voltage into a primary current, a secondary capacitor C1 to which the primary current and the main control current are supplied/ outputted, a resistor R1 connected in parallel with the secondary capacitor and a voltage across the resistor R1 is outputted as a control voltage.


Inventors:
SANO MASAKI
Application Number:
JP1997000036543
Publication Date:
August 09, 1999
Filing Date:
February 20, 1997
Export Citation:
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Assignee:
NIPPON DENKI KK
International Classes:
G11B20/14; H03L7/093; (IPC1-7): H03L7/093; G11B20/14
Domestic Patent References:
JP62293818A
JP1098376A
JP56119520A
JP9312565A
JP6276090A
JP6164383A
JP4227332A
JP3136522A
JP786930A
JP9205362A
Attorney, Agent or Firm:
後藤 洋介 (外1名)