JP2000047749A - Electronic equipment, and operation state switching method for electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably switch the output current of a power circuit when the electronic equipment is switched between its normal state and standby state. SOLUTION: When the electronic equipment is switched from the normal state to the standby state, a master clock 131 supplied in the normal state is stopped and a microcomputer power circuit operation mode switching signal XSTBY121 is outputted in a subclock operation state to switch the power source operation circuit mode to a small-current mode. When the equipment is switched from the standby state to the normal state, the microcomputer power circuit operation mode switching signal XSTBY121 is outputted in the sublock operation state to switch the power source operation circuit mode to a large-current mode, and then the master clock 131 begins to be supplied, so that the normal state is entered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to switching of an operating state of an electronic device, and more particularly to an electronic device and a method of switching an operating state of an electronic device, which stably switch an output current of a power supply circuit when switching between a normal state and a standby state. .

[0002]

2. Description of the Related Art Conventionally, an electronic device equipped with a microcomputer has a normal mode in which the microcomputer controls a controlled part of the electronic device in a normal mode, and a standby mode in which the microcomputer stops a process. There are many. In the standby mode, it is necessary to reduce power consumption as much as possible for energy saving. In particular, it is essential for battery-operated electronic devices to minimize battery consumption. A microcomputer mounted in such an electronic device can often operate with two types of clocks, a high-frequency master clock and a low-frequency subclock. In this case, the master clock is a clock for performing a normal process for executing a main function of the electronic device. The subclock is a clock for mainly operating a clock function and the like.

When an electronic device is in a normal mode, a master clock is supplied to a microcomputer to perform a normal operation. Also, a sub clock is supplied as needed.

On the other hand, when the electronic device is in the standby mode, the supply of the master clock is stopped because it is not necessary to execute the normal operation. The standby mode is generally further divided into a sub clock mode and a sleep mode. The sub clock mode is a state in which the master clock is stopped but the sub clock is operating, and is used when it is necessary to always operate the clock function. In the sleep mode, both the master clock and the sub clock are stopped.

Since the current consumption of the microcomputer is proportional to the frequency of the clock, the current consumption is considerably smaller in the standby mode in which the master clock is stopped than in the normal mode. For this reason, the power supply circuit that supplies power to the microcomputer needs to output a large current in the normal mode, but not in the standby mode.

FIG. 5 is a circuit diagram of a conventional power supply circuit.
The power supply circuit 113 includes C1, C2, and C3 for smoothing the current.
And a Zener diode D1, a resistor R1, a transistor T
R1; a power supply input V; a power supply for the microcomputer; and output to the microcomputer. By passing a current from R1 to the Zener diode D1, the base voltage of TR1 becomes almost constant regardless of the voltage of the power supply input, and the output is stabilized. When the microcomputer is in the normal mode, a large current is required, and the resistance value of R1 is reduced so that the voltage does not decrease with respect to the maximum current.
Is smaller, the current consumed by the power supply circuit increases. Even in the standby mode in which the output current is small, the current flows in the same manner, so that the consumed current is the same as in the normal mode.

For this reason, in the normal mode and the standby mode,
By switching this resistance value depending on the operation mode, there is a mode in which the normal mode is a large current mode in which a large amount of current flows, and the standby mode is a small current mode in which the current is small.

A description will now be given of the operation state switching of a conventional electronic device that performs such a current mode switching. FIG.
9 is a flowchart of a conventional method for switching the operation state of an electronic device.

When the process is started (S301), the electronic device equipped with the microcomputer performs a reset process (S3).
02). By the reset processing, the operation state of the microcomputer becomes the normal mode, and the power supply circuit operation mode becomes the large current mode.

In the normal mode state, it is checked whether there is a request to shift to the standby mode (S30).
3). If there is no request to shift to the standby mode, control of the controlled unit, which is a normal process, is performed (S30).
4). When the control of the controlled unit (S304) is completed, a loop process is executed in which the process is started again from the transition request check to the standby mode (S303) via the path P315.

When a request to shift to the standby mode is issued, a power supply circuit switching command is issued to the power supply circuit so that the power supply circuit operation mode is set to the small current mode (X
STBY = “L”) (S305). Then, after the power supply circuit operation mode is changed to the small current mode, the master clock is stopped, and the mode shifts to the sub clock mode which is the standby mode (S306). Further, if there is a sleep mode request (S307), the sub clock is stopped and the mode shifts to the sleep mode (S308). Then, when the sleep mode is released (S309), the sub clock is oscillated to shift to the sub clock mode (S310).

In the subclock mode, the normal processing is stopped and the operation is performed only by the subclock, and it is checked whether there is a subclock mode release request (S311). If there is no subclock mode release request, the sleep mode request check (S307) process is started again via the path P314. If there is a subclock mode release request, the master clock is oscillated to shift to the normal mode (S312).
Then, after shifting to the normal mode, a switching command is issued so that the power supply circuit operation mode is set to the large current mode (XSTBY = “H”) (S313). After the transition to the normal mode, the process proceeds to the standby mode request check (S303), which is the normal mode processing, via the path P315.

[0013]

However, in a conventional electronic device and a method for switching the operation state of the electronic device, the operation mode of a power supply circuit for supplying power to a microcomputer is switched in a normal mode in which a master clock is supplied. Because
There is a problem that the operation of the microcomputer becomes unstable.

For example, during the transition from the normal mode to the standby mode in the section a in FIG. 6 and the transition from the standby mode to the normal mode in the section b, the power supply circuit operation mode is the small current mode, The process performed in the normal mode that requires a current is executed, the voltage drop of the power supply increases, and the operation becomes unstable.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and has been made in view of the above circumstances. When an electronic device is switched between a normal state and a standby state, the output current of a power supply circuit is stably switched. It is an object to provide a switching method.

[0016]

According to the present invention, in order to solve the above-mentioned problems, in an electronic device having a normal state and a standby state, switching between a large current mode and a small current mode is performed by a power supply circuit operation mode switching signal. A possible power supply circuit,
A clock generation circuit for generating a high-frequency master clock and a low-frequency subclock, and switching between the normal state and the standby state of the electronic device by outputting the power supply circuit operation mode switching signal while the master clock is stopped And an electronic device provided with a control unit that performs the following.

In the electronic device having such a configuration, when switching between the normal state and the standby state, the power supply circuit operation mode switching signal is output in the sub clock operation state in which the master clock is stopped to switch the power supply operation circuit mode.

In the method of switching the operation state of an electronic device having a normal state and a standby state, the supply of the master clock is stopped in a normal state in which a master clock is supplied and a power supply circuit operation mode is a large current mode. A procedure in which the power supply circuit operation mode is switched from the normal state to the standby state by switching the power supply circuit operation mode to the small current mode while operating only with the clock, and a power supply circuit operation mode in which only the subclock is supplied and the power supply circuit operation mode is the small current mode Switching the power supply circuit operation mode to the high current mode in the standby state,
Switching the operation state of the electronic device from the standby state to the normal state by starting supply of the master clock, and a method of switching the operation state of the electronic device.

According to the method for switching the operation state of an electronic device in such a procedure, the transition from the normal state to the standby state is performed by stopping the master clock when the power supply circuit operation mode is the large current mode, and thereafter, Is set to the small current mode, and shifts to the standby state. In the transition from the standby state to the normal state, the power supply circuit operation mode is set to the large current mode, and then the master clock is supplied to transition to the normal state.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electronic device according to an embodiment of the present invention. The electronic device receives a power supply input V for supplying power and a power supply input V, and a control unit (
Power supply circuit 110 for generating power supply for microcomputer 120
A microcomputer 120 that is supplied with power by the power supply circuit 110 and controls the entire electronic device; a clock generation circuit 130 that generates a clock to be supplied to the microcomputer 120; And a unit 140. Such electronic devices include CD players, TVs, VTRs, radios and the like. The power supply to the power supply circuit 110 includes an AC power supply and a battery.

The power supply circuit 110 receives a power supply input V and generates and supplies power for driving the microcomputer 120.
The power supply circuit 110 has a power supply circuit operation mode
There are two types of modes, a large current mode for supplying a large current and a small current mode for supplying a small current. The switching of the power supply circuit operation mode is performed according to the instruction of the power supply circuit operation mode switching signal (XSTBY) 121 output from the control unit 120.

The microcomputer 120 operates by receiving power supply from the power supply circuit 110. The operation states of the microcomputer 120 are classified into a normal mode in which the microcomputer 120 controls the controlled unit 140 of the electronic device and a standby mode in which such normal processing is stopped. The selection of the operation state is performed by an operation mode switching signal input to the microcomputer 120 from the outside. An operation clock for operating the microcomputer 120 is supplied by the clock generation circuit 130. In the case of the normal mode, a master clock 131 having a high frequency and a sub-clock 132 having a low frequency are supplied as necessary to perform predetermined processing. On the other hand, in the case of the standby mode, the master clock 13
1 is stopped, the subclock 132 is supplied as needed, and the normal processing is stopped.

As described above, the operation state of the microcomputer 120 can be divided into a normal mode in which the master clock 131 is operating and a standby mode in which the master clock 131 is stopped. The standby mode is generally further divided into a sub clock mode and a sleep mode. The sub clock mode is a state in which the supply of the master clock 131 is stopped but the sub clock 132 is supplied, and is used when it is necessary to always operate the clock function. In the sleep mode, the supply of both the master clock 131 and the subclock 132 is stopped.

The clock generation circuit 130 includes the microcomputer 12
0 is generated. The generated clock includes a high-frequency master clock (several MHz to several tens of MHz) 131 and a low-frequency subclock (3
There are two types of clocks of 132). The master clock 131 is a clock for the microcomputer 120 to execute the normal mode, and the subclock 132 is a clock for operating the clock function and the like.

The controlled unit 140 is a main functional unit of the electronic device that operates according to an instruction from the microcomputer 120. For example, a CD player implements functions such as a signal reading unit, a signal amplifying unit, and a sound output unit.

Since the current consumption of the microcomputer is proportional to the frequency of the clock, a large current is required in the normal mode in which the master clock 131 is operating, the master clock 131 stops, and only the sub clock 132 operates. In the sub clock mode, no large current is required. In this case, the frequency of the master clock is several MHz to several tens of MHz, and the frequency of the sub clock is 32 kHz.
Therefore, the power consumption in the sub clock mode is about 1/100 of that in the normal mode.

Therefore, the microcomputer 120 sets the power supply circuit operation mode to the large current mode in the normal mode in which the master clock 131 operates, and sets the power supply circuit operation mode to the small current mode in the standby mode in which the master clock 131 stops. And

Next, a power supply circuit according to an embodiment of the present invention will be described in detail. FIG. 2 is a circuit diagram of a power supply circuit 111 according to an embodiment of the present invention. In the normal mode, TR2 is off. In this case, a current is passed from the R1 to the Zener diode D1 to make the TR1
Is substantially constant regardless of the voltage of the power supply input. The emitter terminal of TR1 has a base voltage of -0.6.
V, and the microcomputer power output is also substantially constant. At this time, (collector current ≒ output current) is applied to the base of TR1.
A current of hfe (current amplification degree) flows. For example, hfe
= 100, when the output current is 100 mA, about 1 mA flows through the base. When hfe is the same and the output current is 1 mA, 0.01 mA flows to the base. Since the current flowing to the base is supplied from R1, if the current flowing from R1 and R2 is considered to be constant, the current flowing to the Zener diode will change. That is, when the output current changes, the current of D1 changes. If the current flowing through the base is sufficiently smaller than the current flowing through D1, the voltage fluctuation is small, but if it cannot be ignored, the voltage fluctuation becomes large. In order to obtain a large output current, it is necessary to lower the resistance value of R1 and constantly supply a large current to D1. Since this current is consumed by this circuit, it is a useless current if the current consumption is small. Therefore, the resistance value is switched between when the output current is large and when the output current is small. The power supply circuit operation mode switching signal for performing this switching is XSTBY. If the output current is small, X
STBY = “L”, TR3 and TR2 are turned off, and R
No current flows through 2. That is, the base current of D1 and TR1 is supplied only by R1. R1 has a large resistance value and is set to a value that allows the minimum necessary current to flow through D1, thereby reducing current consumption. When the output current is large, XSTBY = “H”
To turn on TR3 and TR2 so that current flows through R2. That is, D1 and TR1 in R1 // R2
Supply base current. The resistance of R2 has a small voltage drop even when the output current is large (base current is large).

Next, the switching operation of the electronic device having the above configuration and the method of switching the operation state of the electronic device will be described. FIG. 3 is a flowchart of a method for switching an operation state of an electronic device according to the present invention.

When the processing of the electronic device according to the present invention is started (S201), first, a reset processing is performed (S2).
02). By this reset processing, the operation state of the electronic device becomes the normal mode, and the power supply circuit operation mode becomes the large current mode.

In the normal mode state, it is checked whether there is a request to shift to the standby mode (S20).
3). If there is no request to shift to the standby mode, control of the controlled unit, which is a normal process, is performed (S20).
4). When the control of the controlled part (S204) ends, a loop process is executed in which the process is started again from the request to shift to the standby mode (S203) via the path P215.

If there is a request to shift to the standby mode, the master clock of the clock generation circuit 130 is stopped, and the mode shifts to the subclock mode (S205). Thereafter, a power supply operation mode switching command is issued to the power supply circuit so that the power supply circuit operation mode is set to the small current mode (XSTBY = “L”) (S206).

After the power supply circuit operation mode is changed to the small current mode, if there is a sleep mode request (S20)
7) Stop the sub clock and shift to the sleep mode (S208). When the sleep mode is released (S209), the sub-clock is oscillated to shift to the sub-clock mode (S210).

The subclock mode is a state in which the subclock mode is only operated, and a minimum process such as a clock process is performed to check whether or not there is a subclock mode release request (S211). If there is no subclock mode release request, the sleep mode request check (S207) process is started again via the path P214.

When a command to shift to the normal mode, that is, a subclock mode release request is issued, a power circuit operation mode switching command is issued so that the power circuit operation mode is set to the large current mode (XSTBY = “H”). ") (S
212). Thereafter, the master clock is oscillated to shift to the normal mode (S213). After shifting to normal mode,
The processing proceeds to the standby mode request check (S203), which is the normal mode processing, via the path P215.

In the above description, the device is provided with the sleep mode. However, the same processing is performed for a device not provided with the sleep mode. That is, the steps of the sleep mode processing (S208 to S210) are omitted from the check of the presence or absence of the sleep mode request (S207) in FIG.

Conversely, the same processing is performed when there is no sub clock mode. That is, the check of the presence or absence of the sleep mode request (S207) and the check of the presence or absence of the subclock mode release request (S211) in FIG. 3 are omitted, and the sleep mode processing (S208 to S210) is always executed.

In the above description of the power supply circuit 111,
The switching of the power supply circuit operation mode is performed by the switching circuit including TR2 and TR3.
A signal that becomes H "may be used. FIG. 4 is a circuit diagram of a power supply circuit of an electronic device according to another embodiment of the present invention.
The signal supplied to the diode D2 is "H" in the normal mode.
This is one of the operation signals that becomes “L” in the standby mode. In the normal mode, that is, when the output current is large, the signal OMS becomes "H", and a current flows to R2 through the diode D2. That is, the base currents of D1 and TR1 are supplied at R1 // R2. Meanwhile, standby mode,
That is, if the output current is low,
L ", and no current flows through R2.
Only supplies the base current of D1 and TR1. The diode D2 is necessary to prevent a current from flowing backward during standby.

The above processing functions can be realized by a computer. In this case, the processing content of the function that the microcomputer operation state switching unit should have is described in a program recorded on a computer-readable recording medium. Then, by executing this program on a computer, the above processing is realized on the computer. Examples of the computer-readable recording medium include a magnetic recording device and a semiconductor memory. When distributing in the market, CD-ROM (Compact Disk Read Only)
The program may be stored and distributed in a portable recording medium such as a memory or a floppy disk, or stored in a storage device of a computer connected via a network, and transferred to another computer via the network. When the program is executed by the computer, the program is stored in a hard disk device or the like in the computer, and is loaded into the main memory and executed.

[0040]

As described above, according to the present invention, the switching between the normal state and the standby state is performed by switching the power supply circuit operation mode while the master clock is stopped. It is possible to prevent the power supply from becoming unstable due to the supply of the master clock in the mode. Further, since the switching is performed stably, it is not necessary to extraly estimate the power during standby, and it is possible to minimize the power.

In the microcomputer operating state switching method of the present invention, the switching between the normal state and the standby state is performed by switching the power supply circuit operating mode while the master clock is stopped. Since the power supply circuit operation mode is the large current mode, stable operation can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a power supply circuit of an electronic device according to an embodiment of the present invention.

FIG. 3 is a flowchart of a method for switching an operation state of an electronic device according to an embodiment of the present invention.

FIG. 4 is a circuit diagram of a power supply circuit of an electronic device according to another embodiment of the present invention.

FIG. 5 is a circuit diagram of a power supply circuit of a conventional electronic device.

FIG. 6 is a flowchart of a conventional method for switching the operation state of an electronic device.

[Explanation of symbols]

110 power supply circuit, 111 power supply circuit of one embodiment of the present invention, 112 power supply circuit of another embodiment of the present invention,
Reference numeral 113: conventional power supply circuit, 120: control unit (microcomputer), 121: XSTBY (power supply circuit operation mode switching signal), 130: clock generation circuit, 131: master clock, 132: subclock, 140: controlled part

Claims (4)

[Claims] An electronic device having a normal state and a standby state, a power supply circuit capable of switching between a large current mode and a small current mode by a power supply circuit operation mode switching signal, a high frequency master clock and a low frequency low frequency A clock generation circuit that generates a sub clock; and a control unit that outputs the power supply circuit operation mode switching signal in a state where the master clock is stopped to switch between a normal state and a standby state of the electronic device. Electronic equipment characterized by the above. 2. The power supply circuit operation mode switching signal,
2. The electronic device according to claim 1, wherein the signal is a signal generated in a predetermined normal process, the signal being turned on when the operation state of the electronic device is in a normal state, and being turned off in a standby state. 3. A method for switching an operation state of an electronic device having a normal state and a standby state, wherein the supply of the master clock is stopped in a normal state in which a master clock is supplied and a power supply circuit operation mode is a large current mode. A procedure in which the power supply circuit operation mode is switched from the normal state to the standby state by switching the power supply circuit operation mode to the small current mode while operating only with the clock, and the power supply circuit operation mode in which only the subclock is supplied is the small current mode Switching the power supply circuit operation mode to the high current mode in the standby state, and starting supply of the master clock to switch the operation state of the electronic device from the standby state to the normal state. How to switch the operating state of the device. 4. A computer-readable recording medium on which an operation state switching processing program for an electronic device having a normal state and a standby state is recorded, wherein a master clock is supplied and a power supply circuit operation mode is a large current mode. Stopping the supply of the master clock, switching the power supply circuit operation mode to the small current mode while operating only with the subclock, and switching the operation state of the electronic device from the normal state to the standby state; and The power supply circuit operation mode is switched to the high current mode in the standby state where the power supply circuit operation mode is the small current mode, the supply of the master clock is started, and the operation state of the electronic device is changed from the standby state to the normal state. Read the computer that records the switching procedure and the program that causes the computer to execute Capacity recording medium.