JPH07322605A - Switching circuit for power supply line - Google Patents

Abstract

PURPOSE:To provide a low-power-consumption circuit without generating a feedthrough current from a power supply line to a grounding part for a switching circuit for power supply line for operating a circuit requiring a large voltage by boosting a low power supply voltage. CONSTITUTION:The circuit is provided with a ring oscillation circuit l for outputting a specific pulse signal, a charge pump circuit 2 for obtaining a specific output voltage by boosting the voltages of the ring oscillation circuit 1 and a power supply line Vcc, a switch 5 for grounding for connecting the output part of the charge pump circuit 2 to a grounding part Vss due to the operation stop of the ring oscillation circuit 1, and a control gate 3 for controlling the switch 5. A switch 6 for disconnecting power supply line which is cut by a signal from the control gate 3 is provided between the power supply line Vcc and the grounding line Vss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply line switch circuit for operating a circuit requiring a large voltage by boosting a low power supply voltage. Such a circuit is used in a portable device using a battery as a driving source, and it is required to reduce power consumption as much as possible.

[0002]

2. Description of the Related Art FIG. 5 is a circuit diagram for explaining a conventional power line switching circuit. The conventional power supply line switch circuit includes a ring oscillator circuit 11, a charge pump circuit 12 that boosts the power supply voltage Vcc by the operation of the ring oscillator circuit 11, a load circuit operation switch 14 that operates by the boosted voltage, and a boosting stop time. Switch 15 for grounding consisting of a bipolar transistor for performing abrupt off operation of
And a control gate 13 for controlling the grounding switch 15.

The ring oscillation circuit 11 is composed of, for example, C-MOS inverters connected in odd stages, and outputs a constant pulse signal. Further, the charge pump circuit 12 is
As shown, the two-stage C-MOS inverter IV11,
IV12, bipolar transistors Tr15 to Tr19 and capacitors C1 to C4 forming a voltage converter
Is equipped with.

The pulse signal output from the ring oscillator circuit 11 is divided into two signals having opposite phases by the two-stage CMOS inverters IV11 and IV12.
11 through the capacitors C11 and C13 to the bases of the transistors Tr15 and Tr17 and the inverter IV1.
2 is input to the bases of the transistors Tr16 and Tr18 via the capacitors C12 and C14.

The power supply line Vcc has a bipolar transistor T
Ring oscillator circuit 1 connected to the emitter of r15
1 signal causes bipolar transistors Tr15 to Tr15
A voltage converter composed of 18 output terminals A '
The voltage at the point is gradually increased. The output A'point of the voltage converter is at N which constitutes the load circuit operating switch 14.
It is connected to the gate of the MOS transistor, and when the voltage at the point A ′ reaches, for example, 12 V, the NMOS transistor 14 is turned on, and the circuit in the subsequent stage (not shown) operates.

When turning off the NMOS transistor 14, the ring oscillation circuit 11 is stopped and the grounding switch 15 is turned on by the control gate 13 to quickly bring the input portion of the NMOS transistor to the ground level. If the voltage value at this input decreases, the NMO
The S transistor 14 is turned off. The above circuit is used for operating a floppy disk drive which requires a voltage of 12V in a portable personal computer or the like which operates at 3V to 5V. For example, a floppy disk drive is used. If not, the switch circuit is turned off to reduce power consumption.

[0007]

In the above conventional power line switching circuit, when the grounding switch 15 is turned on by the operation of the control gate 13, the power line V
Multi-stage bipolar transistors Tr15 to Tr19 forming a voltage converter in the direction from cc to the ground portion Vss
Therefore, a through current is generated from the power supply line Vcc to the ground portion Vss as indicated by an arrow in the figure.

As described above, the shoot-through current is generated when the grounding switch 15 is in the ON state, which causes an increase in power consumption, and especially when a battery is used as a power source in a portable device. The increase of B has a great influence on the battery life. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a low power consumption power line switch circuit that has no shoot-through current.

[0009]

A power line switching circuit of the present invention for solving the above problems is connected to a ring oscillation circuit 1 for outputting a predetermined pulse signal, the ring oscillation circuit 1 and a power line Vcc. , A charge pump circuit 2 that obtains a predetermined output voltage by boosting the voltage of a power supply line Vcc by the operation of the ring oscillator circuit 1, and an output part of the charge pump circuit 2 is grounded when the operation of the ring oscillator circuit 1 is stopped. Switch 5 for grounding, which is connected to the section Vss to set it to the ground level,
It has a control gate 3 for controlling the switch 5, and a power line disconnection switch 6 which is disconnected by a signal from the control gate 3 is provided between the power line Vcc and the ground portion Vss. I am trying.

[0010]

According to the power line switch circuit of the present invention,
By interlocking with the operation of the control gate 3 for turning on the ground switch 5, the power line disconnection switch 6 between the power line Vcc and the ground portion Vss is turned off, so that the power source Vcc is connected to the ground portion Vss. The current path can be disconnected.

For this reason, it is possible to prevent the occurrence of a through current, and it is possible to reduce the power consumption.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a power line switch circuit according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a switch circuit for a power supply line for explaining a first embodiment of the present invention, which includes a ring oscillation circuit 1 and a C-MOS inverter I.
Charge pump circuit 2 having V1 and IV2 and bipolar transistors Tr5 to Tr9 forming a voltage converter, control gate 3, load circuit operation switch 4, power supply line disconnection switch 6, and NPN type controlled by control gate 3 It has a grounding switch 5 composed of a bipolar transistor.

As shown in FIG. 2A, the ring oscillating circuit 1 is formed by connecting inverters IV3 to IV5 in a ring shape, and the output signal is "H" level and "H" level every time this circuit operates. The L "level is repeated at a constant cycle. Therefore, a pulsed signal as shown in FIG. 2B is output at the output point B. In the charge pump circuit 2 (see FIG. 1) to which this pulse signal is input, first the PMOS
A C-MOS inverter IV1 composed of the transistor Tr1 and the NMOS transistor Tr2, and a C-MOS inverter IV2 composed of the PMOS transistor Tr3 and the NMOS transistor Tr4 generate a signal of an opposite phase.

The signal of the inverter IV1 is supplied to the bipolar transistor Tr via the capacitors C1 and C3.
5, the signal of the inverter IV2 which is input to the base of Tr7 and has a phase opposite to that of the inverter IV1 is the capacitor C2.
It is input to the bipolar transistors Tr6 and Tr8 via C4. As described above, the reverse phase pulse signals are alternately input to the four-stage bipolar transistors Tr5 to Tr8, whereby the voltage of the power supply line Vcc is gradually increased.

At the output of the charge pump circuit 2, PM
A power line disconnection switch 6 composed of an OS transistor is connected, but the switch 6 is controlled by the control gate 3 and is normally in an on state.
Therefore, the voltage boosted by the charge pump circuit 2 is input to the gate of the load circuit operating switch 4 including the NMOS transistor via the switch 6. Then, when the output voltage of the charge pump circuit 2 reaches, for example, 12 V, the load circuit operating switch 4 is turned on, and the load circuit (not shown) can operate.

When the operation of the load circuit is stopped, the ring oscillation circuit 1 is stopped and the control gate 3 turns on the grounding switch 5 formed of an NPN bipolar transistor. The grounding switch 5 has a collector connected to the output part of the charge pump circuit 2 and an emitter connected to the grounding part Vss.
When the signal is input to the base to turn it on, the potential of the output portion of the charge pump circuit 2 becomes the ground level, and the load circuit operating switch 4 is instantly cut off.

The signal of the control gate 3 is normally at the "L" level for turning on the PMOS transistor which is the power supply line disconnecting switch 6, and the grounding switch 5
Similarly, the "L" level is input. Therefore NP
Ground switch 5 consisting of N-type bipolar transistor
When turning on, the signal of the control gate 3 is set to "H" level.

In this way, when the control gate 3 outputs an "H" level signal, the grounding switch 5
Is turned on and the power line disconnection switch 6 is turned off. As described in the related art, when the grounding switch 5 is turned on, the emitters of the bipolar transistors Tr5 to Tr9 forming the voltage converter are
The space between the bases is in the forward direction from the power supply line Vcc toward the ground portion Vss.

However, according to this embodiment, when the grounding switch 5 is turned on, the power line disconnecting switch 6 is turned on.
Is turned off, the current path from the power supply line Vcc to the ground portion Vss is cut off, so that a through current which causes an increase in power consumption can be prevented. In this embodiment, the PMOS transistor is used as the power line disconnection switch 6, but another switch such as an NMOS transistor or an NPN type bipolar transistor may be used.

However, when using an NMOS transistor or an NPN type bipolar transistor, it is necessary to provide an inverter between the control gate 3 and the power line disconnection switch to invert the level. Next, a second embodiment of the present invention will be described with reference to the circuit diagram of FIG. In the first embodiment of the present invention, the power line disconnection switch 6 is turned off directly by the signal from the control gate 3, but the charge pump circuit 2 continues to boost the voltage while the ring oscillation circuit 1 is operating. Therefore, the output part of the charge pump circuit 2 to which the power line disconnection switch 5 is connected may have a considerably high voltage.

Since the power supply line disconnection switch 6 does not operate unless a voltage substantially similar to the voltage of the output portion of the charge pump circuit 2 is applied to the gate, a high voltage signal may be required. Therefore, as shown in FIG. 3, a charge pump circuit 6 is provided between the control gate 3 and the power line disconnection switch 6.

After the load circuit operating switch 4 is turned on and a load circuit (not shown) is operated, the ring oscillator circuit 1 is stopped to stop the operation of the load circuit, and the control gate 3 is set to the “H” level. It is the same as in the first embodiment until the grounding switch 5 is turned off by a signal. The signal from the control gate 3 is boosted by the charge pump circuit 6 while turning on the grounding switch 5. The power line disconnection switch 6 is turned off when the signal from the control gate 3 is boosted to a predetermined voltage by the charge pump circuit 7, and the power line is disconnected.

That is, because of the characteristics of the MOS transistor, the operation is performed when a voltage of about +0.8 V is applied to the voltage of the output portion of the charge pump circuit 2. Therefore, the signal of the control gate 3 is generated by the charge pump circuit 7. When this voltage is reached, the power line disconnection switch 6 is turned off, and the current path from the power line Vcc to the ground portion Vss is disconnected.

Since the control gate 3 outputs a signal for the MOS transistor, a buffer circuit 8 for the grounding switch 5 is provided. Next, a third embodiment of the present invention will be described with reference to the circuit diagram of FIG. In this embodiment, the PMOS transistor is provided in the preceding stage of the bipolar transistors Tr5 to Tr9 forming the voltage converter, and is used as the power line disconnection switch 10. That is, the power line disconnection switch 10 is provided in the charge pump circuit 9.

Normally, "L" is output from the control gate 3.
A level signal is output, and this signal is input to the grounding switch 5 composed of an NPN transistor through the power line disconnecting switch 10 and the buffer circuit 8. Therefore, the power supply line disconnection switch 10 formed of the PMOS transistor is turned on, the grounding switch 5 is turned off, and the voltage boosted by the charge pump circuit 9 turns on the load circuit operation switch 4 and the load circuit (not shown). Is working.

When the operation of the load circuit is stopped, the ring oscillation circuit 1 is stopped and the control gate 3 outputs an "H" level signal. This "H" level signal turns on the grounding switch 5 via the buffer circuit 8 and turns off the power line disconnecting switch 9 made of a PMOS transistor.

When the grounding switch 5 is turned on, the voltage at the output of the charge hoop circuit 9 instantly becomes the ground level, and the load circuit operating switch 4 is turned off.
The operation of the load circuit is stopped. Further, since the power line disconnection switch 10 is turned off, the power line Vcc and the ground V
It is possible to disconnect the current path from ss, and it is possible to prevent a shoot-through current that causes an increase in power consumption.

Since the power supply line disconnection switch 10 is provided in the preceding stage of the bipolar transistors Tr5 to Tr9 forming the voltage converter, it can be turned off by a voltage similar to that of the power supply line Vcc. Therefore, it is not necessary to boost the signal of the control gate 3 by a charge pump circuit or the like, and the circuit configuration can be made simpler.

In the present embodiment, the power line disconnection switch 9 is used as a bipolar transistor Tr constituting a voltage converter.
These transistors T are provided in the preceding stages of 5 to Tr8.
It is also possible to provide it so as to intervene between r5 and Tr8.

[0030]

According to the above-described power supply line switch circuit of the present invention, the voltage boosted by the charge pump circuit can be dropped to the ground level and, at the same time, the current path causing the through current can be cut off. Therefore, it is possible to prevent the occurrence of a shoot-through current, and it is possible to reduce the power consumption of the power supply switch circuit used in the portable device.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a ring oscillation operation.

FIG. 3 is a circuit diagram for explaining a second embodiment of the present invention.

FIG. 4 is a circuit diagram for explaining a third embodiment of the present invention.

FIG. 5 is a circuit diagram for explaining a conventional technique.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H03K 17/16 L 9184-5J

Claims (5)

[Claims] 1. A ring oscillator circuit (1) for outputting a predetermined pulse signal, the ring oscillator circuit (1) and a power supply line (Vcc).
Is connected to the charge pump circuit (2) for boosting the voltage of the power supply line (Vcc) by the operation of the ring oscillation circuit (1) to obtain a predetermined output voltage, and the operation of the ring oscillation circuit (1) is stopped. A grounding switch (5) for connecting the output part of the charge pump circuit (2) to a grounding part (Vss) to bring it to the ground level, and a control gate (3) for controlling the switch (5). The power supply line (Vc
A power line disconnecting switch (6), which is provided between c) and a ground portion (Vss) and is disconnected by a signal from the control gate (3). 2. The power supply according to claim 1, wherein the power line disconnection switch (6) is provided between the charge pump circuit (2) and the load circuit operation switch (4). Wire switch circuit. 3. The power supply according to claim 1, wherein the power line disconnection switch (6) is provided in front of a plurality of stages of transistors forming a voltage converter in the charge pump circuit (2). Wire switch circuit. 4. The power line switching circuit according to claim 2, further comprising a charge pump circuit (7) provided between the control gate (3) and the power line disconnecting switch (6). . 5. The grounding switch (5) is an NPN transistor, and the power line disconnection switch (6) is a PMO transistor.
5. The power line switch circuit according to claim 1, wherein the on-off state is always reversed by the signal of the control gate (3) as the S-type transistor.