Title:
CONSTANT-CURRENT DRIVING CIRCUIT
Document Type and Number:
Japanese Patent JP3137095
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To enable a constant-current driving circuit, which drives a load to be subjected to current/voltage conversion and a capacitor connected in parallel with the load by a constant current, to shorten the rising time of the current flowing to the load.
SOLUTION: A capacitor 15 is charged at the time constant determined by a constant-current value from a transistor 8 and the capacitance of the capacitor 15 until its potential reaches a specified voltage which is obtained by converting the constant current of the transistor 8 into a voltage through a load 14. In this case, the reference voltage at the reference voltage terminal 10 of a reference voltage source 9 is set at a value which is smaller than the sum of the specified voltage and the gate-source voltage of a transistor 13. Since a switch 12 is set in continuity synchronously with a control terminal 2 similarly to a switch 11, the capacitor 15 connected in parallel with the load 14 is quickly charged to the voltage through the transistor 13. When the capacitor 15 reaches the voltage, the transistor 13 is disconnected, thereafter, the capacitor 15 is charged to a specified voltage with the constant current of the transistor 8.
Inventors:
Shigeo Nishitoba
Application Number:
JP31084898A
Publication Date:
February 19, 2001
Filing Date:
October 30, 1998
Export Citation:
Assignee:
NEC
International Classes:
G09G3/30; H03K17/04; H03K17/687; (IPC1-7): H03K17/04; G09G3/30; H03K17/687
Domestic Patent References:
| JP3255720A | ||||
| JP2128205A | ||||
| JP58186817A | ||||
| JP546266A | ||||
| JP10322185A |
Attorney, Agent or Firm:
Nobuyuki Kaneda (2 others)
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