Semiconductor integrated circuit device which shortens the transition time between operating and standby states

• US 6,249,174 B1
• Filed: 07/29/1999
• Issued: 06/19/2001
• Est. Priority Date: 02/23/1999
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Tsunezawa, Masakazu
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): ENGLUND, TERRY LEE
• Application Number:
  US09/362,725
• Time in Patent Office: 691 Days
• Field of Search: 327/530, 327/538, 327/374, 327/544, 326/17, 326/83, 365/227
• US Class Current: 327/538
• CPC Class Codes: G05F 3/242 with compensation for device parameters, e.g. channel width modulation, threshold voltage, processing, or external variations, e.g. temperature, loading, supply voltage

Abstract

A reference voltage generator circuit (RG1) includes a voltage generator (GP) having NMOS transistors (M7, M8, M9), PMOS transistors (M10, M11, M12, M13), an inverter (G4) and a resistor (R1), and a discharge path (DP1) having NMOS transistors (M14, M15, M16). The reference voltage generator circuit is capable of reducing the transition time required for a current cell matrix type D-A converter to make a standby-state to operating-state transition.

Claims

1. A semiconductor integrated circuit device comprising:

a first circuit serving as main circuit and including a current source transistor; and

a second circuit for generating a control voltage to be applied to a control electrode of said current source transistor of said first circuit, said second circuit being operative to turn off and on said current source transistor by setting said control voltage at first and second voltages thereby to place said first circuit in a standby state and in an operating state, respectively,

said second circuit comprising;

a current source and an output voltage setting device connected between first and second power supplies, said output voltage setting device setting an output voltage from said current source at said second voltage;

an output end for outputting at least said output voltage from said current source as said control voltage; and

voltage determination means connected between said output end and said second power supply, said voltage determination means forcing voltage of said control electrode of said current source transistor to approach said second voltage when said first circuit is being placed in said operating state.

2. The semiconductor integrated circuit device according to claim 1,

wherein said voltage determination means comprises at least one diode-connected transistor connected between said output end and said second power supply, and

wherein said voltage determination means forces the voltage of said control electrode of said current source transistor to approach said second voltage until the voltage of said control electrode of said current source transistor reaches a threshold voltage of said at least one diode-connected transistor when placing said first circuit in said operating state.

3. The semiconductor integrated circuit device according to claim 2,

wherein said second circuit further comprises

switching means connected between said first power supply and said output end for making and breaking connection between said first power supply and said output end,

wherein said at least one diode-connected transistor of said voltage determination means comprises:

a first transistor of a first conductivity type having a first main electrode connected to said output end, a second main electrode, and a control electrode connected to said first main electrode of said first transistor;

a second transistor of said first conductivity type having a first main electrode connected to said second main electrode of said first transistor, a second main electrode, and a control electrode connected to said first main electrode of said second transistor; and

a third transistor of said first conductivity type having a first main electrode connected to said second main electrode of said second transistor, a second main electrode connected to said second power supply, and a control electrode, and

wherein said switching means comprises

a fourth transistor of a second conductivity type having a first main electrode connected to said first power supply, a second main electrode connected to said output end, and a control electrode,

said control electrodes of said third and fourth transistors receiving a control signal for turning off said third transistor and turning on said fourth transistor when placing said first circuit in said standby state.

4. The semiconductor integrated circuit device according to claim 1,

wherein said voltage determination means comprises at least a transistor connected between said output end and said second power supply,

wherein said second circuit further comprises at least one inverter for on-off controlling said transistor,

said at least one inverter having an input connected to said output end, said transistor being on-off controlled based on an output from said at least one inverter, and

wherein said transistor is held on until the voltage of said control electrode of said current source transistor reaches a threshold voltage of said at least one inverter when placing said first circuit in said operating state.

5. The semiconductor integrated circuit device according to claim 4,

wherein said second circuit further comprises

switching means connected between said first power supply and said output end for making and breaking connection between said first power supply and said output end,

wherein said at least one inverter comprises first and second inverters connected in series,

said first inverter having an input connected to said output end, and an output,

said second inverter having an input connected to said output of said first inverter, and an output,

wherein said at least a transistor of said voltage determination means comprises:

a first transistor of a first conductivity type having a first main electrode connected to said output end, a second main electrode, and a control electrode connected to said output of said second inverter; and

a second transistor of said first conductivity type having a first main electrode connected to said second main electrode of said first transistor, a second main electrode connected to said second power supply, and a control electrode, and

wherein said switching means comprises

a third transistor of a second conductivity type having a first main electrode connected to said first power supply, a second main electrode connected to said output end, and a control electrode,

said control electrodes of said second and third transistors receiving a control signal for turning off said second transistor and turning on said third transistor when placing said first circuit in said standby state.

6. The semiconductor integrated circuit device according to claim 1,

wherein said voltage determination means comprises at least a transistor connected between said output end and said second power supply,

wherein said second circuit further comprises a controller for on-off controlling said transistor, said controller including at least a Schmitt gate,

said Schmitt gate having an input connected to said output end, said transistor being on-off controlled based on an output from said Schmitt gate,

said Schmitt gate having a first threshold voltage for specifying voltage at which said output changes from a first level to a second level, and a second threshold voltage for specifying voltage at which said output changes from said second level to said first level, and

wherein said transistor is held on until the voltage of said control electrode of said current source transistor reaches said first threshold voltage of said Schmitt gate when placing said first circuit in said operating state.

7. The semiconductor integrated circuit device according to claim 6,

wherein said second circuit further comprises

switching means connected between said first power supply and said output end for making and breaking connection between said first power supply and said output end,

wherein said controller further includes an inverter having an input connected to said output of said Schmitt gate, and an output,

wherein said at least a transistor of said voltage determination means comprises:

a first transistor of a first conductivity type having a first main electrode connected to said output end, a second main electrode, and a control electrode connected to said output of said inverter; and

a second transistor of said first conductivity type having a first main electrode connected to said second main electrode of said first transistor, a second main electrode connected to said second power supply, and a control electrode,

wherein said Schmitt gate comprises;

a third transistor of said first conductivity type having a first main electrode connected to said second power supply, a second main electrode, and a control electrode;

a fourth transistor of said first conductivity type having a first main electrode connected to said second main electrode of said third transistor, a second main electrode, and a control electrode;

a fifth transistor of a second conductivity type having a first main electrode connected to said second main electrode of said fourth transistor, a second main electrode connected to said first power supply, and a control electrode; and

a sixth transistor of said first conductivity type having a first main electrode connected to said first main electrode of said fourth transistor, a second main electrode connected to said first power supply, and a control electrode,

said control electrodes of said third, fourth and fifth transistors being connected to said output end,

said control electrode of said sixth transistor being connected to said first main electrode of said fifth transistor serving as said output of said Schmitt gate, and

wherein said switching means comprises

a seventh transistor of said second conductivity type having a first main electrode connected to said first power supply, a second main electrode connected to said output end, and a control electrode,

said control electrodes of said second and seventh transistors receiving a control signal for turning off said second transistor and turning on said seventh transistor when placing said first circuit in said standby state.