JPH04117164A - Charge pump voltage converter - Google Patents

Abstract

PURPOSE:To implement two types of charge pump voltage converters in the form of a monolithic IC without increasing the chip area by sharing a part of switching transistors being employed in the two types of charge pump voltage converters. CONSTITUTION:Elements for generating a one time voltage having reverse polarity are transistors 2-5 and capacitors 6-7. A voltage -V1 having reverse polarity appears at an output terminal 8. Elements for generating a doubled voltage having same polarity are switching transistors 2, 3, 9, 10 and capacitors 13, 14. A voltage 2V1 having same polarity appears at an output terminal 15. When the two switching transistors 2, 3 are shared by charge pump converters having same polarity and reverse polarity, chip area can be reduced as compared with a case where they are implemented in the form of individual monolithic ICs resulting in an inexpensive IC.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a monolithic IC charge pump voltage converter.

[Summary of the invention]

The present invention applies 6N voltage applied from the outside to the same polarity side.
By sharing the elements used in the charge pump voltage converter that multiplies the charge pump voltage converter and multiplies it by 1 on the opposite polarity side, a charge pump voltage converter with a small chip area is realized.

[Conventional technology]

Circuit diagrams of conventional charge pump voltage converters are shown in FIGS. 2 and 3. In Figure 2, the positive voltage is applied to the source terminal 1, the switch transistors 2 to 5 and the capacitor 6
．． 7 is a charge pump voltage converter that generates a voltage -vl of opposite polarity at the output terminal 8. FIG. 3 shows a charge pump voltage that converts the voltage ■ applied to the positive power supply terminal 1 into a voltage 2V+ with the same polarity and doubled at the output terminal 15 by the switch transistors 9 to 12 and the capacitor 13.14. It is a converter.

[Problem to be solved by the invention]

By the way, when it becomes necessary to mount the above two circuits on a monolithic IC, they must be installed separately in Figures 2 and 3.
Since the charge pump voltage converter shown in the figure must be assembled, there is a drawback that the chip area becomes large.

[Means to solve the problem]

The present invention aims to solve the problems of the conventional technology, and has been able to form two types of charge pump voltage converters into a monolithic IC without increasing the chip area.

Specifically, the chip area is reduced by sharing part of the switch 1 transistor used in the two types of charge pump voltage converters.

[Effect]

In the charge pump voltage converter of the present invention, as shown in FIG. 1, since the switch transistors 2 and 3 are shared by two types of charge pump voltage converters, the chip area can be reduced.

〔Example〕

Embodiments of the charge pump voltage converter of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a circuit diagram of a charge pump voltage converter according to the present invention. The element that generates a voltage of 1 times the opposite polarity is
These are switch transistors 2 to 5 and capacitors 6 and 7. When the rectangular wave generated by the oscillation circuit is input from the input terminal I6, the switch transistors 2 and 4 are turned ON, and the capacitor 6 is charged with the voltage 1 input from the positive power supply terminal 1.

In the next half period of the square wave, switch transistors 3 and 5
Since only one terminal of the capacitor 6 is turned on and one end of the capacitor 6 is held at the ground potential, a voltage -1 of the opposite polarity is outputted to the output terminal 8. On the other hand, an element that generates twice the voltage between polarities is
Switch transistor 2.3.9.10 and capacitor 1
3 and 14. Due to the rectangular wave input from the input terminal 16, the switch transistors 9 and 3 are turned ON, and the capacitor 13 receives the voltage ■1 input from the positive power supply terminal 1.
is charged. During the next half cycle of the rectangular wave, only the switch transistors 2 and 10 are turned on, and one end of the capacitor 13 is connected to the positive power source, so that a voltage of 2V of the same polarity is generated at the output terminal 15.

〔Effect of the invention〕

As described above, according to the present invention, the two switch transistors constituting the charge pump voltage converter are shared by the charge pump voltage converters of the same polarity and the opposite polarity, so that each of them is fabricated into a monolithic IC separately. It is possible to reduce the chip area and is cheaper than using
This has the effect of supplying C.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a charge pump voltage converter according to the present invention, and FIGS. 2 and 3 are circuit diagrams of conventional charge pump voltage converters, respectively. 1...Positive power input terminal 2-5, 9.10...Switch transistor 6, 7
．． 13.14... Capacitor 8, ]5... Output terminal or more Applicant: Seiko Electronic Industries Co., Ltd. Agent Patent attorney: Takayuki Hayashi Figure 2 Figure 3

Claims (1)

[Claims] A charge pump voltage converter that generates an output voltage of twice the same polarity and a charge pump voltage converter that generates an output voltage of 1 times the opposite polarity are integrated on the same chip.
In the charge pump voltage converter to be converted to C, two
A charge pump voltage converter characterized in that two switch transistors constituting the reverse polarity single charge pump voltage converter are composed of the same switch transistor.