JPH0530730A - Substrate voltage generating circuit - Google Patents

Abstract

PURPOSE:To obtain a substrate voltage generating circuit, in which current consumption can be reduced at the time of generating a substrate voltage, by providing a charge pump circuit with a binary counter circuit thereby lengthening the period of pulse signal within a range where the substrate voltage level does not drop. CONSTITUTION:A binary counter circuit 2 delivers an output signal for gradually lengthening the pulse period to a charge pump circuit 3 thus driving the charge pump circuit 3. Output signal from the charge pump circuit 3 is fed to a substrate 7 which then produces a substrate voltage. Since the output signal from the binary counter circuit 2 has gradually increasing pulse period, through- current decreases to shorten the driving time of the charge pump circuit 3 thus reducing power consumption of the entire circuit. When the pulse period is too long, a detector circuit 1 judges the potential level of the output signal from the charge pump circuit 3 and delivers a reset signal to the binary counter circuit 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate voltage generating circuit used for semiconductor dynamic RAM and the like.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional substrate voltage generating circuit. In FIG. 4, 11 is a ring oscillator circuit as a pulse generating circuit, and 12 is an output signal of the ring oscillator circuit 11 to determine a substrate potential. The generated charge pump circuit 13 is a substrate.

Next, the operation of the substrate voltage generating circuit will be described with reference to FIG. From the ring oscillator circuit 11 to FIG.
A pulse signal having a constant cycle as shown in (a) is output, the pulse signal is input to the charge pump circuit 12, and the charge pump circuit 12 is driven. Then, the charge pump circuit 12 outputs a charge pump output signal having an output waveform shown in FIG. 5B, the charge pump output signal is transmitted to the substrate 13, and a substrate voltage is generated.

[0004]

As described above, the conventional substrate voltage generating circuit uses the ring oscillator circuit 11 for generating a pulse signal of a constant cycle as a pulse generating circuit, and the constant voltage generated from the ring oscillator circuit 11 is used. Since the charge pump circuit 12 is driven by the periodic pulse signal, there is a problem that the through current of the ring oscillator circuit 11 is large and the current consumption of the entire circuit is large when the substrate voltage is generated. The present invention has been made to solve the above problems, and an object of the present invention is to obtain a substrate voltage generation circuit capable of reducing current consumption when a substrate voltage is generated.

[0005]

In the substrate voltage generating circuit according to the present invention, a binary counter circuit is provided as a pulse generating circuit for controlling the drive of the charge-homp circuit so that the period of the pulse signal can be varied and the substrate voltage can be changed. The period of the pulse signal is lengthened within the range where the level does not decrease.

[0006]

According to the present invention, the cycle of the pulse signal output from the pulse generating circuit is gradually lengthened, the through current per unit time of the pulse generating circuit is reduced, and the drive time of the charge hoop circuit is shortened. Current consumption in the circuit when the substrate voltage is generated is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a substrate voltage generating circuit according to an embodiment of the present invention. In the figure, 1 is a detector circuit for detecting the potential level of the substrate 7, 2 is a binary counter circuit used as a pulse generating circuit, and 3 is a circuit. A charge pump circuit for generating a substrate potential in the substrate 7, a substrate 7, 4,
5, 6 and 8 are signal lines.

Next, the operation of the substrate voltage generating circuit will be described with reference to FIG. The binary counter circuit 2 outputs a counter output signal whose pulse period is gradually lengthened as shown in FIG. 2A, and the counter output signal is input to the charge pump circuit 3 to drive the charge pump circuit 3. .. Then, the charge pump circuit 3 outputs a charge pump output signal having an output waveform as shown in FIG. 2B, and this charge pump output signal is input to the substrate 7 to generate a substrate voltage. At this time, the pulse cycle of the counter output signal output from the binary counter circuit 2 gradually increases, so that the through current of the binary counter circuit 2 decreases and the drive time of the charge pump circuit 3 decreases, so that the entire circuit becomes shorter. Current consumption is reduced.

On the other hand, if the pulse cycle of the counter output signal output from the binary counter circuit 2 becomes too long, the current consumption of the entire circuit decreases, but the number of times the charge pump circuit 3 is driven per unit time decreases. The substrate voltage level becomes too small (close to the level of the dotted line A in FIG. 2B). In this case, the detector circuit 1 determines the potential level of the output signal from the charge pump circuit 3 and outputs the reset signal to the binary counter circuit 2 at the timing shown in FIG. 2 (c). As a result, the cycle of the pulse signal generated from the binary counter circuit 2 is returned to the original short state, and as a result, the potential level of the output signal of the charge pump circuit 3 (voltage level on the substrate) is returned to the original state. .. Then, the series of operations described above is repeated, and a stable substrate voltage is generated while suppressing current consumption.

In the substrate voltage generating circuit of this embodiment, the pulse generating circuit is the binary counter circuit 2, the counter output signal from the binary counter circuit 2 drives the charge pump circuit 3, and the detector circuit 1 The charge pump output level from the charge pump circuit 3 is judged by the above, and when the output level becomes small, the counter cycle of the binary counter circuit 2 is returned to the original state, so that the level of the generated substrate voltage becomes large. The generation period of the pulse signal for driving the charge pump circuit 3 can be lengthened within a range that does not change,
As a result, the shoot-through current of the binary counter circuit 2 is reduced, and the drive time per unit time of the charge pump circuit 3 is reduced, so that the current consumption of the entire substrate generation circuit can be reduced.

Although the detector circuit 1 is used as the binary counter control circuit for resetting the counter cycle of the binary counter circuit in the above embodiment, the timer circuit 9 is used as shown in FIG. Regardless of the (output potential level of the charge pump circuit), even if the binary counter circuit is reset to the original cycle after a certain period of time, the same effect as in the above embodiment can be obtained.

[0012]

As described above, according to the substrate voltage generating circuit of the present invention, the binary counter circuit is used as the pulse generating circuit for determining the drive time of the charge pump circuit, and the charge pump output of the charge pump circuit is used. Since the binary counter control circuit that resets the counter cycle of the binary counter circuit based on the level (substrate voltage level) is provided, the cycle of the pulse signal that drives the charge pump circuit is lengthened within a range in which the substrate voltage does not fluctuate significantly. Therefore, the current consumption of the entire circuit can be reduced, and a stable substrate voltage can be generated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a substrate voltage generating circuit according to an embodiment of the present invention.

FIG. 2 is a diagram showing output signal waveforms of a charge pump circuit, a binary counter circuit, and a detector circuit in the substrate voltage generating circuit shown in FIG.

FIG. 3 is a block diagram showing a substrate voltage generating circuit according to an embodiment of the present invention.

FIG. 4 is a block diagram of a conventional substrate potential generation circuit.

5 is a diagram showing output signal waveforms of a charge pump circuit and a ring oscillator circuit in the substrate potential generation circuit shown in FIG.

[Explanation of symbols]

 1 Detector Circuit 2 Binary Counter Circuit 3 Charge Pump Circuit 4 Signal Line 5 Signal Line 6 Signal Line 7 Board 8 Signal Line 9 Timer 11 Ring Oscillator Circuit 12 Charge Pump Circuit 13 Board

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H03K 19/096 D 6959-5J

Claims (1)

Claim: What is claimed is: 1. A charge pump circuit for outputting a substrate voltage generation signal to a substrate, and a pulse signal for the charge pump circuit.
A binary counter circuit that controls the drive of the charge pump circuit, and a binary counter control circuit that determines the potential level of the output signal from the charge pump circuit and sends a counter reset signal to the binary counter circuit are provided. Substrate voltage generator circuit.