JPH02101510A - Integrated circuit - Google Patents

Abstract

PURPOSE:To obtain an economic circuit with less current consumption by forming an IC constant voltage circuit by means of six transistors including two transistors whose gates are reverse conduting type and whose impurity density differs. CONSTITUTION:The depression type PMOS transistor (TR) 1 where a reference voltage corresponding to a positive side power voltage VDD is added to the gate supplies a constant current to TR 2 and 3 forming an operand amplifier with enhancement type NMOS TR 4 and 5. The constant voltage IC circuit is formed by enhancement type NMOS TR 6 for constant voltage supply and the like in which the gate and a source are respectively connected to the drain of TR 2 and the negative side power voltage VSS and the drain to a load 7. TR 2 and 3 in which the voltage VDD and the drain output voltage of TR 6 are impressed on respective bases have different impurity density of substrates, and they are set to be gate material P type depression type ad the N type enhancement type. The threshold voltage of a work function difference and the sum of a channel dope can be obtained without using the resistances, and the economic constant voltage IC circuit can be obtained with less current consumption.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a watch IC (Integrated C1
rcuit (integrated circuit), etc., which require low power consumption.
This relates to a constant voltage circuit of C.

(Prior Art) Conventionally, a constant voltage circuit has been configured with a circuit that amplifies the input offset voltage of an operational amplifier using resistors 18 and 19, as shown in Fig. 3. (7) MOS transistor 20.
The gate material 21 is composed of P-type polysilicon and N-type polysilicon, and is created by a threshold voltage difference caused by a work function difference between the gate materials.

Alternatively, if the offset voltage of the operational amplifier due to the work function difference is not amplified, the offset voltage itself becomes the output of the constant voltage circuit.

[Problem to be solved by the invention]

However, in conventional constant voltage circuits, in order to obtain the desired voltage, it is necessary to amplify the offset voltage of the operational amplifier due to the work function difference using a resistor, which increases the area of the resistor part and increases the manufacturing cost of the IC. Alternatively, if the area of the resistor portion is made smaller in order to reduce manufacturing costs, the current flowing through the resistor increases, resulting in an increase in the current consumption of the IC.

In addition, in a type of constant voltage circuit that does not use a resistor to amplify the offset voltage of the operational amplifier due to the work function difference, the output voltage of the constant voltage circuit is limited to the work function difference between P-type polysilicon and N-type polysilicon. Therefore, there was a drawback that a voltage other than the work function difference could not be output.

[Means for Solving the Problems] In order to solve the above problems, the integrated circuit of the present invention has the following features: a) The source is connected to a first power supply, and the gate is connected to a first power source.
The first MOS (Metal Oxide Sem1c) of one conductivity type is supplied with a constant voltage based on the power supply of
onductor: metal-oxide film-semiconductor) transistor; b) one conductivity type whose source is connected to the drain of the first (7) MOS transistor and whose gate is supplied with a voltage of the same potential as the first power supply; a second (7) MOS transistor; and C) a third transistor of one conductivity type whose source is connected to the first transistor.

d) A fourth transistor of an opposite conductivity type, whose source is connected to a second power supply, whose drain is connected to the second transistor, and whose gate is supplied with a voltage of the same potential as the drain of the third transistor. a transistor; e) a reverse conductivity type whose source is connected to a second power supply, whose drain is connected to the third transistor, and whose gate is supplied with a voltage of the same potential as the drain of the third transistor; a fifth transistor; g) the gate of the third transistor is supplied with a voltage of the same potential as the drain of the sixth transistor; h) the second transistor and impurity concentrations of the substrates of the third transistor are different; i) the gate of the second transistor is made of polysilicon of one conductivity type; and j) the gate of the third transistor is of the opposite conductivity type. It is characterized by being made of polysilicon.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1 in FIG. 1 is a depletion type PMOS transistor, which serves as a constant current source for an operational amplifier. 2 is a depletion type P in which the gate material polysilicon is P type.
It is a MOS transistor. 3 is an enhancement type NMOS in which the gate material polysilicon is N type.
It is a transistor. 4.5.6 is an enhancement type NMO5I-RANDISC, and the drain of 6 is the output of this constant voltage circuit. Here, when the impurity concentrations of the substrates 2 and 3 are equal as in a conventional constant voltage circuit, a voltage of about -1.1 V with respect to the positive side power supply is output. This outputs the work function difference between P-type polysilicon and N-type polysilicon, and since it is a physical constant, the variation is small, but it cannot be set to any other voltage other than 1.1V. In the constant voltage circuit of
By adding one ion implantation process (hereinafter referred to as channel doping) to the IC manufacturing process, the impurity concentration of the substrates of two or three P-type MOS transistors is differentiated, and the threshold voltage difference other than the work function difference is reduced. The output of the constant voltage circuit can be the sum of the threshold voltage difference due to the work function difference and the threshold voltage difference due to channel doping.For example, the threshold voltage of 2 is 10, 5V, and the threshold voltage of 3 is the work Function difference 1. The sum of IV and channel dope 0.4v,
That is, higher than the threshold voltage of 1.5 V by 2
1. If it is OV, -1.5V with respect to the positive power supply is obtained as the output of the constant voltage circuit.

FIG. 3 shows an example in which a switch 8.16 is connected to control the operation of a constant voltage circuit in order to operate the IC with lower power consumption, and 17 is a control signal.

[Effect of the Invention 1] The effect of the present invention is that since no resistor is used, the area of the constant voltage circuit can be reduced, and a constant voltage circuit with low current consumption can be manufactured at low cost. This is particularly effective for ICs that require a voltage of 1.1 V or more for normal operation of a load circuit, and that require low power consumption, such as a watch IC.

In addition, the P-type MO5I-Landisk in the above explanation is N.
Type MO3! - The same effect can be obtained even if the transistor is replaced with a transistor, the N-type MOS transistor is replaced with a P-type MOS transistor, the positive power supply is replaced with a negative power supply, and the negative power supply is replaced with a positive power supply.

[Brief explanation of the drawing]

FIG. 1 is a constant voltage circuit diagram of the present invention. FIG. 2 is a constant voltage circuit diagram of the present invention in which a switch is connected to a power source. FIG. 3 is a conventional constant voltage circuit diagram. l...Depression type PMO3I-constant current circuit using transistor 2...Gate material is P-type polysilicon Depression type PMO3I-Rangis 3...Gate material is N-type polysilicon and channel dope is implanted Enhancement type PMOS transistor 4... Enhancement type NMOS transistor 5... Enhancement type NMO 3) Transistor... Enhancement type NMOS transistor 7... Load circuit 8... PMOS transistor 9 for positive side power switch...・Constant current circuit 10 using depression type PMO5I-transistor...Depression type PMOS transistor 11 whose gate material is P-type polysilicon...Gate material is N-type polysilicon, 14, 18, 19, 20, channels Doped enhancement-type PMOS transistor, enhancement-type NMOS transistor, enhancement-type NMOS transistor, enhancement-type NMOS) transistor, load circuit, NMOS transistor for negative side power switch, control signal to control the operation of the constant voltage circuit, Resistor for amplifying voltage output / Resistor for amplifying constant voltage output / Depletion type PMOS transistor whose gate material is P-type polysilicon ・Enhancement type PMOS transistor whose gate material is N-type polysilicon Applicant: Seiko Epson Corporation Representative Patent Attorney Masayoshi Kamiyanagi (and 1 other person) vef) Constant current circuit 2 using a depressigon type PMO3 transistor; Depletion type PMOS transistor 3 whose gate material is P-type polysilicon; , N-type polysilicon, channel doped enhancement type PMOS transistor 4.5, 6; enhancement type NMOS) Langistaffe; load circuit Figure 2 Figure 1

Claims (2)

[Claims] (1) a) A first MOS (Metal Oxide Semiconductor) of one conductivity type, whose source is connected to a first power supply and whose gate is supplied with a constant voltage based on the first power supply.
b) one conductivity type whose source is connected to the drain of the first (7) MOS transistor and whose gate is supplied with a voltage of the same potential as the first power supply; c) a third transistor of one conductivity type, the source of which is connected to the first transistor, and d) the source of which is connected to a second power supply, and the drain of which is connected to the second transistor. e) a fourth transistor of an opposite conductivity type, whose gate is connected to the drain of the third transistor and whose gate is supplied with a voltage of the same potential as the drain of the third transistor; e) whose source is connected to a second power supply and whose drain is connected to the third transistor; f) a fifth transistor of an opposite conductivity type, which is connected to the transistor No. 3 and whose gate is supplied with a voltage of the same potential as the drain of the third transistor; g) a sixth transistor of an opposite conductivity type, to which a voltage of the same potential as the drain of the second transistor is supplied, and at least one load is connected to the drain; h) the substrates of the second transistor and the third transistor have different impurity concentrations, i) An integrated circuit characterized in that: the gate of the second transistor is made of polysilicon of one conductivity type, and j) the gate of the third transistor is made of polysilicon of the opposite conductivity type. (2) The integrated circuit according to claim 1, further comprising means for controlling on/off of the first power source or the second power source.