JP3332131B2 - Standby / operation control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a standby / operation control circuit suitable for portable equipment and the like, and more particularly to a standby / operation control circuit in which current consumption during standby is reduced.

[0002]

2. Description of the Related Art As a circuit in which a normal voltage is applied during operation and current consumption is reduced during standby, there is a circuit shown in FIG. 6, reference numeral 1 denotes a controlled circuit such as an amplifier, which includes a signal input terminal 11, a signal output terminal 12, and a power supply terminal 1.
3, a ground terminal 14, a reference voltage terminal 15, and a switch terminal 16. The controlled circuit 1 is a circuit in which when the switch terminal 16 has a low level voltage, the reference voltage terminal 15 switches to a high impedance state and enters a standby state.

A control circuit 2 controls a switch terminal 16 and a switch S1 of the controlled circuit 1 by inputting a control signal. R1 and R2 are resistors for setting a reference voltage applied to the reference voltage terminal 15, and C1 stabilizes the reference voltage applied to the reference voltage terminal 15 (for example, in a vehicle-mounted device, engine noise is superimposed on the power supply voltage). The power supply voltage becomes unstable.)

In the circuit shown in FIG. 6, the switch S1 is controlled to be turned off by the control circuit 2 during standby, and the switch terminal 16 of the controlled circuit 1 is set to a low level voltage. At this time, as described above, the controlled circuit 1 is in a standby state because the reference voltage terminal 15 has a high impedance, thereby reducing current consumption. Further, no current flows through the resistor R2 for generating the reference voltage. After the voltage of the capacitor C1 reaches the power supply voltage Vcc, no current flows through the resistor R1, so that the current consumption is reduced.

Next, in operation, the control circuit 2 controls the switch S1 to be turned on, and applies a high-level voltage to the switch terminal 16 of the controlled circuit 1. At this time,
The controlled circuit 1 enters an operating state, and the voltage at the reference voltage terminal 15 switches from the power supply voltage Vcc to a reference voltage obtained by dividing the power supply voltage Vcc by the division ratio of the resistors R1 and R2. Thus, the controlled circuit 1 is released from the standby state and starts operating.

FIG. 7 is a diagram showing another example of a conventional circuit.
The same components as those in the circuit of FIG. 6 are denoted by the same reference numerals. The difference from the circuit of FIG. 6 is that a switch is not connected to the resistor R2, and a switch S2 is connected between the resistor R1 and the power supply. Therefore, during standby, the resistance R
1 and R2 are completely separated from the power supply, the current consumption of that part becomes zero, and the voltage applied to the reference voltage terminal 15 becomes the ground potential. During operation, the voltage of the reference voltage terminal 15 switches from the ground potential to a reference voltage obtained by dividing the power supply voltage Vcc by the division ratio of the resistors R1 and R2.

[0007]

However, in the circuits shown in FIGS. 6 and 7 described above, when switching from the standby state to the operating state, the voltage of the reference voltage terminal 15 of the controlled circuit 1 becomes the normal reference voltage. It takes time to reach this point, during which time the reference voltage continues to fluctuate, and it takes some time to start normal operation of the controlled circuit 1, that is, the response to the control signal applied to the control circuit 2 is poor. is there.

It is an object of the present invention that when switching from the standby state to the operating state, this is done quickly and the standby / standby mode is such that the voltage at the reference voltage terminal instantaneously reaches the normal reference voltage.
An operation control circuit is provided.

[0009]

According to a first aspect of the present invention, there is provided a standby / operation control circuit comprising: a reference voltage generation circuit for generating a reference voltage proportional to a power supply voltage; a reference voltage terminal to which the reference voltage is input; A controlled circuit having a switch terminal to which a control signal for switching between standby and operation of the circuit is input;
A standby / operation control circuit including a control circuit for sending the control signal to the switch terminal of the controlled circuit, wherein the control circuit transmits the control signal to the switch terminal of the controlled circuit. A reference voltage stabilizing circuit configured by connecting a capacitor between the power supply and the power supply, the switch means for separating from the ground,
The control circuit sends a control signal for standby to the controlled circuit and the switch means, so that the controlled circuit is in a standby state and the switch means switches the reference voltage generation circuit to the power supply. Separate from ground,
In addition, the control circuit is set to an operation state by sending a control signal for operation, and the reference voltage generation circuit is connected to the power supply and the ground by the switch means.

According to a second aspect of the present invention, in the first aspect, the switch means comprises a semiconductor element, and the control circuit controls the semiconductor element so that the semiconductor element is cut off during standby and the internal resistance becomes a predetermined value during operation. The switch means is configured to also serve as the reference voltage generation circuit.

According to a third aspect of the present invention, in the first aspect, the above-mentioned controlled circuit switches standby / operation of an internal circuit by supplying / cutting off current to a switch terminal. Is configured to be controlled by the switch means.

[0012]

According to the first aspect of the present invention, the reference voltage generating circuit is separated from the power supply during standby, and the controlled circuit enters the standby state, thereby reducing current consumption. When switching from standby to operation, the voltage at the reference voltage terminal of the controlled circuit changes from the voltage applied by the reference voltage stabilization circuit to the voltage determined by the reference voltage generation circuit, but it takes time for the voltage to settle to the latter voltage. Are very short and the switching is rapid.

According to the second aspect of the present invention, since the switch means also serves as the reference voltage generating circuit, the circuit configuration is simplified.

According to the third aspect of the present invention, the switch means simultaneously controls the switch terminals of the controlled circuit, thereby simplifying the circuit configuration.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. FIG. 1 is a diagram for explaining the principle. The same components as those in the circuits of FIGS. 6 and 7 are denoted by the same reference numerals.

In the present invention, resistors R1 and R2 (reference voltage generation circuit) for determining a reference voltage applied to the reference voltage terminal 15
, Switches S3 and S4 (switch means) are respectively connected in series, and capacitors C2 and C3 (reference voltage stabilizing circuit) are respectively connected to a series circuit of the switch S3 and the resistor R1 and a series circuit of the switch S4 and the resistor R2. ) Are connected in parallel. The capacitors C2 and C3 are connected to the power supply voltage Vc
This is to stabilize the power supply voltage Vcc by absorbing noise mixed into the reference voltage c and stabilize the reference voltage applied to the reference voltage terminal 15. The switches S3 and S4 are controlled by the control circuit 2.

In the circuit shown in FIG. 1, a control signal for standby is transmitted by the control circuit 2 so that the reference voltage terminal 1
5 becomes high impedance, and the internal function of the controlled circuit 1 stops. Further, the switches S3 and S4 are turned off.
From the above, the current consumption becomes almost zero.

Next, by sending a control signal for operation from the control circuit 2, the controlled circuit 1 starts functioning, switches S3 and S4 are turned on, and the reference voltage terminal 15 is connected to the resistors R1 and R2. The determined reference voltage is input, and the operation state is established.

Here, immediately before the transition from the standby state to the operation state, the potential of the reference voltage terminal 15 is set to the capacitor C2,
A voltage obtained by dividing the power supply voltage Vcc by C3 (the resistance R1,
R2), the voltage does not fluctuate during the transition to the operating state, and reaches the reference voltage determined by the resistors R1 and R2 very quickly. Therefore, the controlled circuit 1 immediately starts normal operation.

FIG. 2 is a diagram showing a first embodiment of the present invention. Here, as the controlled circuit 1 shown in FIG. 1, a controlled circuit 4 whose standby state / operating state is switched depending on the presence or absence of a current input is used. 41 is an input terminal,
42 is an output terminal, 43 is a power supply terminal, 44 is a ground terminal, 4
5 is a reference voltage terminal, 46 is a current terminal (corresponding to a switch terminal). This current terminal 46 is connected to the collector of the transistor Q2 of the current mirror circuit including the pnp transistors Q1 and Q2. The collector of the transistor Q1 is connected to the switch S3. Further, a resistor R3 is connected between the common connection point of the resistors R1 and R2 and the reference power supply terminal 45.

In the first embodiment, when the switches S3 and S4 are turned off by a signal input to the control terminal 3,
The transistors Q1 and Q2 are turned off, the controlled circuit 4 cuts off the current to the current terminal 46 and enters a standby state, and the reference voltage terminal 45 becomes high impedance. Next, when the signals input to the control terminal 3 are switched to turn on the switches S3 and S4, the transistors Q1 and Q2 are also turned on, and the controlled circuit 4 is supplied with a current to the current terminal 46 to be in an operating state. A reference voltage is applied to the reference voltage terminal 45.

FIG. 3 is a diagram showing a second embodiment. This is because the switch S3 in the first embodiment is replaced with a p-channel FET Q3, the switch S4 is replaced with an n-channel FET Q4, and a resistor R4 and an n-channel FET Q5 are provided for controlling the p-channel FET Q3.
FE is divided by resistors R5 and R6.
The input is made to the gates of TQ4 and Q5.

In the circuit of the second embodiment, the control terminal 3
To a low level voltage, the FETs Q4 and Q5 are turned off, and when the FET Q5 is turned off, the FET Q3 is also turned off, the transistors Q1 and Q2 are turned off, the controlled circuit 4 enters a standby state, and the current of the resistors R1 and R2 becomes It becomes zero. Also, by setting the control terminal 3 to a high level voltage, the FET
Q4 and Q5 are turned on, and the FE is turned on by turning on the FET Q5.
TQ3 is also turned on, and transistors Q1 and Q2 are turned on to be in an operating state.

FIG. 4 is a diagram showing a third embodiment. This is because the transistors Q1 and Q2 in the second embodiment are replaced with p-channel FETs Q6 and Q7, respectively, and the functions of the resistor R1 and the switch S3 of the reference voltage generating circuit are replaced by the functions of the resistor R2 and the switch S4. This is realized by the n-channel FET Q8. Others are the same as those of the second embodiment.

In the circuit of the third embodiment, the control terminal 3
Is set to a low level voltage, the FETs Q5 to Q8 are turned off, and a standby state is set. When the control terminal 3 is set to a high level voltage, the FET Q5 is turned on, and the FET Q5 is turned on.
When the switch 5 is turned on, the FETs Q6 and Q7 are also turned on to be in an operating state. Also, the FET Q8 is turned on. Reference voltage terminal 45
Is a voltage obtained by dividing the power supply voltage Vcc by the internal resistance of the FETs Q6 and Q8.

FIG. 5 is a diagram showing a fourth embodiment. This means that the switch S3 of the first embodiment shown in FIG.
The switch Q4 is realized by an npn transistor Q10 by a transistor Q9, and an npn transistor Q11 is provided to drive the transistor Q9. The resistor R7 is for biasing the transistor Q11, and the resistor R8 is for biasing the transistor Q10.

In the circuit of the fourth embodiment, the control terminal 3
Are set to a low level voltage, the transistors Q1 and Q
2. All of Q9 to Q11 are turned off, and a standby state is set.
When the control terminal 3 is set to a high-level voltage, all of them are turned on to be in an operation state.

[0028]

As described above, according to the first aspect, the reference voltage stabilizing circuit is constituted by two capacitors connected in series between the power supply and the ground, and the two capacitors are connected in common. Since the point is connected to the reference voltage terminal of the controlled circuit,
When the resistance element of the reference voltage generating circuit connected to the reference voltage terminal is cut off → connected, the voltage applied to the reference voltage terminal does not greatly change, and when the state of the controlled circuit is changed from the standby state to the operating state. The internal DC voltage quickly settles to a predetermined value. According to the second invention,
Since the switch means also serves as the reference voltage generation circuit, the circuit configuration is simplified. Further, according to the third aspect, since the switch means simultaneously controls the switch terminals of the controlled circuit, the circuit configuration is simplified also in this respect.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a standby / operation control circuit for explaining the principle of the present invention.

FIG. 2 is a circuit diagram of a standby / operation control circuit according to the first embodiment.

FIG. 3 is a circuit diagram of a standby / operation control circuit according to a second embodiment.

FIG. 4 is a circuit diagram of a standby / operation control circuit according to a third embodiment.

FIG. 5 is a circuit diagram of a standby / operation control circuit according to a fourth embodiment.

FIG. 6 is a circuit diagram of a conventional standby / operation control circuit.

FIG. 7 is a circuit diagram of another conventional standby / operation control circuit.

[Explanation of symbols]

 1, 4: controlled circuit, 2: control circuit, 3: control terminal.

Claims (3)

(57) [Claims] 1. A reference voltage generating circuit for generating a reference voltage proportional to a power supply voltage, a reference voltage terminal to which the reference voltage is input, and a switch to which a control signal for switching between standby and operation of an internal circuit is input. A controlled circuit having a terminal;
A standby / operation control circuit comprising: a control circuit for sending the control signal to the switch terminal of the controlled circuit, wherein the control circuit transmits the control signal between the reference voltage terminal and the power supply, and the reference voltage terminal and the ground. A reference voltage stabilizing circuit configured by connecting a capacitor therebetween, and switch means for separating the reference voltage generating circuit from a power supply and ground, wherein the control circuit comprises the controlled circuit and the switch means By sending a control signal for standby, the controllable circuit is set to a standby state and the switch means separates the reference voltage generation circuit from the power supply and ground,
A standby / operation control circuit, wherein the controlled circuit is set in an operation state by transmitting a control signal for operation, and the reference voltage generation circuit is connected to the power supply and the ground by the switch means. 2. The switch means comprises a semiconductor element.
2. The semiconductor device according to claim 1, wherein the semiconductor device is turned off in a standby state, and the semiconductor device is controlled by the control circuit so that an internal resistance becomes a predetermined value during operation, and the switch means also serves as the reference voltage generation circuit. A standby / operation control circuit as described. 3. The circuit according to claim 1, wherein said controlled circuit switches between standby and operation of an internal circuit by supplying / cutting a current to a switch terminal. The supply / cutoff of a current to said switch terminal is controlled by said switch means. 2. The standby / operation control circuit according to claim 1, wherein: