Semiconductor integrated circuit device and electronic appliance

• US 20040227555A1
• Filed: 04/30/2004
• Published: 11/18/2004
• Est. Priority Date: 05/01/2003
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Mano, Tatsuya
• Granted Patent: US 7,088,164 B2
• Time in Patent Office: Days
• US Class Current: 327/291
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters

Abstract

When main power is turned on by a switch SW, a pulse shaper 12 feeds a pulse signal having a pulse width Tp through an OR circuit 14 to a power supply circuit 2a to turn it on. Moreover, a delay generator 13a gives the pulse signal a delay and then feeds it to a control signal generator 15a so that a microcomputer 3 is turned on with a delay corresponding to the length of time required by the power supply circuit 2a to start up.

Claims

1. A semiconductor integrated circuit device comprising:

a clock generator that generates a clock signal for time-keeping even when main power to an electronic appliance is off;

a drive control signal generator that generates a drive control signal by which is driven a power supply circuit that supplies a supply voltage to a main controller that controls the electronic appliance as a whole;

a state control signal generator that generates a state control signal by which is controlled an operation state of the main controller; and

a timing controller that controls operation timing of a remaining part of the electronic appliance other than the main controller,

wherein the drive control signal generator, the state control signal generator, and the timing controller are logic circuits that operate based on the clock signal from the clock generator, and

wherein whether the main power to the electronic appliance is on or off is checked so that, based on whether the main power is on or off, supply of electric power to individual blocks of the electronic appliance is controlled.

2. A semiconductor integrated circuit device as claimed in claim 1,

wherein, a predetermined length of time after the drive control signal generator outputs the drive control signal, the state control signal generator outputs the state control signal.

3. A semiconductor integrated circuit device as claimed in claim 1,

wherein the clock generator generates the clock signal with a frequency lower than a clock frequency used when the main power to the electronic appliance is on, and the clock generator is constantly operating.

4. A semiconductor integrated circuit device as claimed in claim 1,

wherein the drive control signal generator comprises:

a pulse shaper that generates, from a first pulse signal indicating turning-on and turning-off of the main power to the electronic appliance, a second pulse signal having a pulse length longer than a length of time that the main controller requires to start up and shut down; and

an OR gate that receives a start-up completion indicating signal indicating starting-up and shutting-down of the main controller along with the second pulse signal from the pulse shaper to output the drive control signal to the main controller.

5. A semiconductor integrated circuit device as claimed in claim 4,

wherein the state control signal generator comprises:

a delay generator that gives the first pulse signal indicating the turning-on and turning-off of the main power to the electronic appliance a delay longer than a length of time required by the power supply circuit that supplies the main controller to start up.

6. A semiconductor integrated circuit device as claimed in claim 5, further comprising:

a chatter eliminator that eliminates chatter from the first pulse signal indicating the turning-on and turning-off of the main power to the electronic appliance,

wherein the first pulse signal having chatter eliminated therefrom is fed to the pulse shaper and to the delay generator.

7. An electronic appliance comprising:

main power that turns on and off the electronic appliance;

a clock generator that generates a clock signal that permits the electronic appliance to operate; and

a time-keeping circuit that keeps time,

wherein, when the main power is on, the entire electronic appliance operates by using a high-frequency main clock signal from the clock generator and, when the main power is off, only the time-keeping circuit operates by using a low-frequency sub clock for time-keeping from the clock generator, and

wherein an operation for taking in an input signal is performed by using the sub clock after the main power is turned from off to on until a high-speed operation is started.