Current driving device

• US 7,995,047 B2
• Filed: 12/12/2007
• Issued: 08/09/2011
• Est. Priority Date: 12/13/2006
• Status: Active Grant

• Current Assignee: Bishop Display Tech LLC (IP Edge LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Mizuki, Makoto, Nishi, Kazuyoshi, Ohmori, Tetsuro, Kojima, Tomokazu, Kojima, Hiroshi
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): CHOWDHURY, AFROZA Y
• Application Number:
  US11/954,659
• Publication Number:
  US 20080143429A1
• Time in Patent Office: 1,336 Days
• Field of Search: 345/76, 345/204, 327/108
• US Class Current: 345/204
• CPC Class Codes: G05F 3/26 Current mirrors

Abstract

A current driving device comprises: a voltage supply part; a current supply part; and a plurality of current output parts, each comprising a current-voltage converting function, a voltage-current converting function, and a voltage holding capacitance element. The current output part takes three operation modes. Under a voltage supply mode, the current output part receives a voltage from the voltage supply part and holds the voltage in the voltage holding capacitance element. Under a current supply mode, the current output part receives the current from the current supply part, generates a second voltage by the current-voltage converting function and holds the voltage in the voltage holding capacitance element. Under a current output part, the current output part outputs an output current according to the voltage held in the voltage holding capacitance element by the voltage-current converting function. By charging the current output part with the reference voltage before the calibration performed by using the reference current, calibration of the current output part is performed at a high speed.

Claims

1. A current driving device, comprising:

a first voltage supply source for supplying a first voltage;

a first current supply source for supplying a first electric current;

a plurality of output terminals; and

a plurality of current output circuits for outputting an electric current in accordance with said first electric current, each of said current output circuits comprising a current-voltage converting circuit, a voltage-current converting circuit, a voltage holding circuit having a terminal being connected to a reference voltage different from the first voltage, and at least one current output terminal, wherein;

each of said current output circuits operates in three operation modes including a voltage supply mode, a current supply mode, and a current output mode,

under said voltage supply mode, each of said current output circuits receives said first voltage from said first voltage supply source, and the first voltage is supplied to another terminal of said voltage holding circuit,

under said current supply mode, each of said current output circuits receives said first current from said first current supply source, and generates a second voltage by said current-voltage converting circuit, and the first current is supplied to said another terminal of said voltage holding circuit, and

under said current output mode, each of said current output circuits outputs an output current according to said voltage held in said voltage holding circuit by said voltage-current converting circuit.

2. The current driving device according to claim 1, wherein:

each of said output terminals is connected to said current output terminals provided to said plurality of said current output circuits, and

each of said plurality of current output circuits is connected in parallel to said first current supply source and said first voltage supply source used in common.

3. The current driving device according to claim 1, wherein, in each of said current output circuits, said current-voltage converting circuit is actuated under said voltage supply mode.

4. The current driving device according to claim 1, wherein each of said current output circuits is configured to stop said current-voltage converting circuit under said voltage supply mode.

5. The current driving device according to claim 1, further comprising:

a second current supply source for supplying a second electric current that is proportional to said first electric current; and

a second current-voltage converting circuit for generating said first voltage by receiving said second electric current, wherein

said first voltage supply source controls supplies of said first voltage generated by said second current-voltage converting circuit to said current output circuits.

6. The current driving device according to claim 5, wherein said second current-voltage converting circuit comprises a switching part for short-circuiting a node at which said first voltage emerges to a reference voltage node.

7. The current driving device according to claim 1, further comprising a second voltage supply source with a larger voltage supply capacity than that of said first voltage supply source, wherein

the use of said first voltage supply source and the use of said second voltage supply source are switched in accordance with the number of said current output circuits that operate in said voltage supply mode among said plurality of current output circuits.

8. The current driving device according to claim 1, wherein

said first voltage supply source is configured to change its voltage supply capacity in accordance with the number of said current output circuits that operate in said voltage supply mode among said plurality of current output circuits.

9. A current-driving-type display device, comprising said current driving device according to claim 1 mounted thereon so as to be driven by said current driving device.

10. A current driving device, comprising:

a current input switch for controlling connection/disconnection states with respect to a current supply source;

a voltage holding circuit for holding a reference voltage, which is charged by a flown current, the voltage holding circuit having a first terminal and a second terminal, the first terminal being connected to a fixed voltage;

a calibration switch interposed between said current input switch and said voltage holding circuit;

a plurality of voltage-current converting elements for generating an electric current in accordance with said reference voltage held in said voltage holding circuit;

a plurality of signal response switches that are on/off controlled in accordance with inputted signals, each of said response switches being connected in series to a corresponding one of said voltage-current converting elements, and each of which being connected in parallel to said calibration switch;

a connection node provided between said current input switch and said calibration switch;

a plurality of current output switches, each being interposed between the connection node and said plurality of current output terminals; and

a high-speed switch for controlling connection/disconnection states of said voltage supply source with respect to the second terminal of said voltage holding circuit.