JPS5912629A - Semiconductor circuit - Google Patents

Abstract

PURPOSE:To charge a load of a large capacity up to a potential of a constant voltage power supply in high speed and to reduce the power consumption by stopping a positive feedback loop until its operation becomes important for operating efficiently the positive feedback loop. CONSTITUTION:A transistor(TR)T24 is kept conductive until a gate potential of a TRT23 goes to a value close to a value (Vcc-VT21) being the subtraction of the threshold voltage VT21 of a TRT21 from a power supply voltage Vcc, and the potentil at an output terminal 0 is kept to a value close to a ground level so as not to activate the positive feedback loop. When the TRT24 is conductive and the potential difference between the gate and the source of the TRT23 is as large as the (Vcc-VT21), the positive feedback loop is operated. Since the conductivity of the TRT23 is large in this case, the efficiency of the positive feedback is high and the load of the large capacity is charged up in high speed.

Description

[Detailed description of the invention] The present invention is directed to semiconductor circuits.

Conventionally, the circuit shown in Figure 1 has been proposed as a circuit for this building. First, the configuration and operation of the conventional circuit shown in FIG. 1 will be explained in detail.

In the conventional circuit of FIG. 1, there is an enhancement type insulated gate field effect transistor (hereinafter abbreviated as E-I GF'ET) T11 whose drain and gate are connected to a constant power supply Vcc VC, and whose drain is connected to the source of To. E-I whose gate is connected to input terminal I and whose source is grounded
GFET T12 and E-IGFET T whose drain is connected to VCG K and whose gate is connected to the source of T+t.
13, an E-IGFET T14 whose drain is connected to the source of T13 and becomes the output terminal O, whose gate is connected to the input terminal chain and whose source is connected, Tla
It is composed of a capacitor inserted between the gate and source of the transistor. In FIG. 1, CL is the load capacitance attached to the output terminal Ovc.

Next, the operation of the conventional circuit shown in FIG. 1 will be described. For convenience of explanation, it is assumed that the conventional circuit shown in FIG. 1 is constructed entirely of N-channel insulated gate field effect transistors. First, when the input signal supplied to input terminal Ix changes from high level to low level, T12 to 1 and 14 change from a conductive state to a non-conductive state, and 'I'
The potential of the source of ll, that is, the gate potential of 'l'1a, increases toward the low level or the high level, and T
When the threshold voltage of T13 is exceeded, 'l'1g changes from a non-conductive state to a conductive state VC, and rises to the potential of the source of T13, that is, the potential of output terminal 0. The increase in the potential of the source of Txs contributes to the increase in the gate potential of 1゛13 via the coupling capacitor iC1l, forming a positive feedback loop, and changing the gate potential of T13 to the potential of the constant voltage power supply Vcc (Vcc level). Since it can be made higher, set ff V to the output terminal 0.
CC level output can be obtained. Conversely, when the input signal supplied to the input terminal changes from low level to high level, T12 and T14 change from a non-conducting state to a conducting state, and T13i changes from a conducting state to a non-conducting state, so that the output terminal The potential of O drops from the Vcc level to the ground potential level.

That is, the conventional circuit shown in FIG. 1 operates as an inverter, and when the output is at a high level r;
Since either E-IGFB'l' is in a non-conducting state, power consumption is also low. However, the first
It has been found that the conventional circuit shown in the figure is essentially unsuitable when high-speed switching operation is required.

The reason is described below.

In the conventional circuit shown in FIG. 1, when the input signal falls from high level to low level, 5T1att'l immediately becomes non-conductive, 'l'12 becomes non-conductive, and the gate of 'l'ts is charged through T11. , T13 becomes conductive, at the same time the potential of the output terminal O, that is, Ill 1
Ts begins to rise to the potential of the source of 3, and Ts
By further raising the gate potential of a, the positive feedback loop starts working, but the fact that the positive feedback loop starts operating at the same time as Tla becomes conductive is the reason for the efficiency of the positive feedback loop. is looking down. That is, when T13 becomes conductive, the potential of the output terminal O also rises, and a positive feedback loose that pushes up the gate potential of Ill and 3 via Co begins to operate, but the gate potential of T13 decreases from the Vcc level to the threshold voltage of Tll, VTII. Yet: -vr+ is charged by charging through Tll regardless of the presence or absence of a positive feedback loop until it becomes t)
It is possible to raise the gate potential of T13 by about 1j, but on the other hand, it is necessary to push up the gate potential of 'hs by positive feedback loose. Since the potential of the output terminal O has already increased for the region where
This is because if the four electric currents of 'ta cannot be made large, the efficiency of the positive feedback loop decreases, making high-speed switching impossible. In other words, in order to make the Q1 positive feedback loop work efficiently and charge the large capacity load CL at high speed, the potential of the output terminal 0 must be kept close to the ground level until the gate potential of TI3 reaches (Vcc - VTI l). ~, the region where it is necessary to push up the gate potential of T13 by a positive feedback loop, that is, the gate potential of T13 is (Vcc-VTII
) In the above region, it is necessary to increase the conductivity of Ill, 3 by increasing the potential difference between the gate and source of T13, but in the conventional circuit shown in FIG.
When the circuit becomes conductive, the potential of the output terminal O rises immediately, which has the disadvantage that high-speed switching cannot be achieved.The purpose of the present invention is to improve the drawbacks of the conventional circuit shown in FIG. It is possible to quickly handle large-capacity loads without sacrificing the advantage of low power consumption of conventional circuits.
To provide a semiconductor circuit that can charge up to cc level
There is C.

In the semiconductor circuit of the present invention, a first insulated gate of an enforcement type whose drain and gate are connected to a constant voltage power supply is connected to a field effect transistor, and a drain is connected to a source of the first insulated gate field effect transistor. , a second insulated gate field effect transistor of an enforcement type, whose gate is an input terminal and whose source is grounded;
A third insulated gate field effect transistor of an enhancement type or tiplesion type whose drain is connected to the constant voltage power supply and whose gate is connected to the source of the first insulated gate field effect transistor 1 [the drain of which is connected to the source of the field effect transistor; is connected to the source of the third insulated gate field effect transistor and serves as an output terminal; a fourth enhancement type insulated gate field effect transistor whose source is grounded; and a fourth insulated gate field effect transistor whose source is connected to the second insulated gate field effect transistor. a fifth insulated gate field effect transistor of an enhancement type, the gate of which is connected to the gate of the first insulated gate field effect transistor, the gate of which is connected to the source of the first insulated gate field effect transistor, and whose drain is connected to the gate of the fourth insulated gate field effect transistor; an enhancement transistor having a drain connected to the constant voltage 8E power supply, a gate connected to the gate of the second insulated gate field effect transistor, and a source connected to the gate of the fourth insulated gate field effect transistor; and a capacitor having one end connected to the gate of the third insulated gate field effect transistor and the other end connected to the source of the third insulated gate field effect transistor. It is characterized by having been.

The present invention will be described in detail using FIG. 2, which is a circuit diagram of an embodiment of the present invention.

The circuit according to the embodiment of the present invention shown in FIG. 2 is an E-IGF E whose drain and gate are connected to a constant low voltage power supply, VCC
T T21 and the drain are connected to the source of T21,
The gate is connected to the input terminal I, the source is grounded, and fc
E-IGFET T22, drain is Vcc V
E −jGFE with C gate connected to the source of T21
T T23 and B-10F whose drain is connected to the source of T23 and whose output terminal is 0 and whose source is grounded.
E-IGFE'f' whose source is connected to the gate of T22, whose gate is connected to the source of T21, and whose drain is connected to the gate vc of T24; whose source is connected to the drain of T25, whose gate is connected to the gate of T22; ,)”RainyjEVcc KHzoku'Gshifc E-4
It is composed of a capacitor C21 inserted between the gate and source of GFET T26 and T23. Also CLr
[, is the load capacitance attached to output terminal 0.

Next, the operation of the circuit of the present invention will be explained using FIG. In this case as well, the explanation will be given assuming that all N-channel insulated gate field effect transistors are used. T26 becomes non-conductive, but T24 maintains the conductive state, and then the source potential of 'l'z1, that is, the gate potential of T23 and T2B rises, and the threshold voltage of 'I'25 and the threshold of T23 increase. When the voltage is exceeded, T23 and T211i change from non-conductive state to conductive state almost at the same time, but the gate potential of T24 is affected by E-IG1='ET f! I
, t has a small channel 1 collapse and a long channel length E
- If IGFBT is used, the speed at which the gate potential of T24 moves toward the ground potential can be slowed down, so the output terminal O
Even if the potential 1qTza is in a conductive state, it can be kept at a potential close to the ground level. When the gate potential of T24 further decreases and becomes below the threshold voltage of T24, T24
Since it becomes almost non-conductive, the potential of output terminal 0 rises and C
Raise the gate potential of T23 through 21fL T230
4' The positive feedback loop that further deepens the RL degree and causes a higher voltage to appear at the output terminal ultimately raises the potential of the output terminal O to the CC level, similar to the conventional circuit shown in Figure 2.1. It is. However, in the case of the circuit of the present invention, T23 and T211 become conductive at the same time,
Furthermore, since the discharge path of the charge at the gate of T24 is through T25, by setting the channel length and channel width of 'l'2s to appropriate values, the gate potential of T23 can be adjusted from approximately ■CCt to the threshold voltage of T21. T24 until the value obtained by subtracting VT21, that is, the value close to (Vcc - VTR)
Since it is possible to keep T24 in a conductive state and keep the potential of the output terminal O close to the ground level so that the positive feedback loop does not operate, T24 becomes non-conductive and the positive feedback loop described above is activated. The potential difference between the gate and source of T23 when it operates is as large as (Vcc - VTR), and the conductivity of T23 is high, so the efficiency of the positive feedback loop is high, and it is suitable for quickly charging a large capacity load. This is advantageous, and of course, the positive feedback loop has good pushing efficiency, so
The potential of the output terminal 0 can charge the load capacitor CL to the Vcc level in a short time.

Conversely, when the input signal supplied to the input terminal CH changes from low level to high level, T26 becomes conductive, T22 becomes conductive, and Tzsrc becomes non-conductive, so the gate potential of T23 changes to the ground level T24 Since the gate becomes high level, T23 becomes non-conductive.
As a result of T24 becoming conductive, the potential of the output terminal O becomes ■C
The change from the C level to the ground level is the same as in the conventional circuit shown in FIG. 1, and the power consumption is also the same as in the conventional circuit.

As explained above, in the conventional circuit shown in Fig. 1, the positive feedback loop starts operating at an early stage, which reduces the efficiency of pushing up, and furthermore, the potential difference between the gate and source of T13 becomes small, so the positive feedback loop starts operating at an early stage. When the function of the feedback loop is important, its efficiency decreases and high-speed switching operation is inhibited, but according to the semiconductor circuit of the present invention, the positive feedback loop can be Because the circuit was devised to stop T2 until it becomes important, the positive feedback loop works extremely efficiently and
Since the gate potential can be pushed up while the potential difference between the gate and source of 3 is large, it is possible to handle large-capacitance loads at high speeds.
It is possible to obtain a circuit that can be charged to the cVCC level and has low power consumption.

In addition, in the detailed explanation of the present invention in FIG. 2, T23μE
-IGFET has been described, but the principle of operation is exactly the same and there is no problem even if a Dilgeon type insulated gate field effect transistor is used. However, in this case, when the potential of the a output terminal is at a low level, a current flows steadily through T23 and 'P24, so the power consumption increases, but on the other hand, the degradation type insulated gate field effect Compared to an E-IGFET of the same size, the conductivity of the transistor is higher at the same gate potential, so it has the advantage of being able to realize a circuit with a higher voltage.In addition, in the explanation, it is an N-channel insulated gate field effect transistor. uses a P-channel insulated gate field effect transistor7? Of course, even in the + case, the effect of the present invention is the same as in the N channel case.

[Brief explanation of the drawing]

Figure 1 μ-dependent circuit circuit. Circuit diagram of an embodiment of the semiconductor circuit of the present invention 0T21. T22. T23
゜T24, Tzs, TT26 enhancement type insulated gate field effect transistor. C21,C
LlI:l: Capacity.

Claims (1)

[Claims] an enhancement type first insulated gate field effect transistor having a drain and a gate connected to a constant voltage power supply; a drain connected to the source of the first insulated gate field effect transistor, the gate serving as an input terminal, and the source being grounded; an enhancement type V second insulated gate field effect transistor, and an enhancement type or tigretion type V transistor whose drain is connected to the constant voltage power supply and whose gate is connected to the source of the first insulated gate field effect transistor. a fourth insulated gate field effect transistor of an enhancement type whose drain is connected to the source of the third insulated gate field effect transistor and serves as an output terminal, and whose source is grounded; is connected to the gate of the second insulated gate field effect transistor, the gate is connected to the source of the first insulated gate field effect transistor, and the drain is connected to the gate of the fourth insulated gate field effect transistor. a fifth insulated gate field effect transistor of the type, a drain connected to the constant voltage power supply and a gate connected to the gate of the second insulated gate field effect transistor;
an enhancement type sixth insulated gate field effect transistor having a source connected to the gate of the fourth insulated gate field effect transistor, one end connected to the gate of the third insulated gate field effect transistor, and the other end connected to the gate of the third insulated gate field effect transistor; A semiconductor circuit comprising a capacitor connected to the source of the third insulated gate field effect transistor.