JPH02276469A - Switching regulator integrated circuit - Google Patents

Abstract

PURPOSE:To miniaturize a transistor and increase the efficiency of the same by a method wherein the gate voltage of a control transistor for a switching regulator is supplied from the output voltage of a charge pump voltage converter. CONSTITUTION:The same input voltage and a clock from an oscillator 7 are supplied to a switching regulator 10 and a charge pump voltage converter 11. Further, the output terminal 4 of the charge pump voltage converter 11 is connected to the switching regulator 10 and is used as the power source of an AND gate, constituting the switching regulator 10. when a voltage is inputted from an input terminal 1, the voltage of the output terminal 4 becomes several times of the input voltage and is inputted into the switching regulator 10 while the voltage of the output terminal 2 becomes several times of the input voltage. According to this method, the ON resistance of a control transistor may be reduced. the transistor may be miniaturized and the efficiency of the same may be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a monolithic IC switching regulator.

[Summary of the invention]

The present invention provides high efficiency by providing a switching regulator and a charge pump voltage converter on a monolithic IC, and supplying a voltage for driving a control transistor in the switching regulator from the output voltage of the charge pump voltage converter. This realizes a switching regulator IC.

[Conventional technology]

A circuit diagram of a conventional switching regulator is shown in FIG. 2. A voltage Vin is inputted from an input terminal 1 and outputted to an output terminal 2 through a coil and a diode. Output terminal 2
is input to the difference amplifier via a resistor, and controls the output voltage at output terminal 2. The outputs of the error amplifier and the oscillator 7 are each input to the gate of the control transistor 3 via an AND gate 8. Since the operating principle of the zero-wire circuit is widely known, the explanation will be omitted here. The factors that determine the efficiency of a regulator include the DC resistance of the coil, the forward voltage and turn-on time of the diode, and the ON resistance of the control transistor.When converting a circuit into a monolithic IC, the coil and diode are excluded. Therefore, the ON resistance of the control transistor 3 is required for the IC in order to improve efficiency. If the ON resistance is low, the loss in this part will be small, so a highly efficient switching regulator can be obtained. However, the power supply of the AND gate 8 that drives the control transistor 3 is
Since it is supplied from the input voltage Vin, when this voltage is low, the control transistor 3 is switched on to reduce the ON resistance.
The channel length W must be made very large, which increases the chip area, which is unrealistic. Furthermore, when the channel length W is increased, the leakage current increases, resulting in a loss of energy stored in the coil, which has the disadvantage that the efficiency decreases.

[Means to solve the problem]

The present invention aims to solve the problems of the conventional technology, and has been able to realize a highly efficient switching regulator without increasing the transistor size.

Specifically, a switching regulator and a charge pump voltage converter are provided on the same chip, and the A that drives the control transistor in the switching regulator.
The power supply voltage of the ND gate is supplied from a voltage twice the voltage Vin generated by a charge pump voltage converter that receives the voltage Vin as an input.

〔Example〕

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

FIG. 1 is a block diagram of a switching regulator according to the present invention. The switching regulator 10 and the charge pump voltage converter 11 have the same input voltage Vi.
A clock is supplied from n and an oscillator 7. Furthermore, the output terminal 4 of the charge pump voltage converter 11 is connected to the switching regulator 10 and is used as a power source for the AND gate 8 (see FIG. 2) that constitutes the switching regulator 10.

Immediately after the voltage Vin is input from the input terminal l, the voltage Vir+L is not output to the output terminals 2 and 4, but the output increases as time passes, and the value set by the resistor is output to the output terminal 2. A voltage twice the voltage Vin appears at the terminal 4. (Here, FIG. 3 shows a circuit diagram of the charge pump voltage converter 11 that can obtain twice the output voltage. The configuration and operating principle of this circuit are widely known, so their explanation will be omitted here.) Therefore, the gate voltage of the control transistor 3 (see Figure 2) in the switching regulator is initially the voltage Vin, but increases to twice the voltage Vin as time passes.
In a steady state, the ON resistance of the control transistor 3 can be made very small. In addition, since the load current that the charge pump voltage converter 11 should supply is only the charging and discharging current of the gate capacitance of the control transistor 3, the capacitor 5.6 required by the charge pump voltage converter 11 (see FIG. 3) The value of can be made quite small, and there is also the possibility of on-chip implementation.

〔Effect of the invention〕

As described above, according to the present invention, the switching regulator and the charge pump voltage converter are provided on the same chip, and the gate voltage of the control transistor in the switching regulator is supplied from the output voltage of the charge pump voltage converter. This has the effect of realizing a highly efficient switching regulator even when the input voltage is low.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a switching regulator of the present invention, FIG. 2 is a circuit diagram of a conventional switching regulator, and FIG. 3 is a circuit diagram of a charge pump voltage converter. 3...Applicant for control transistors and above Patent attorney Keinosuke Hayashi, agent for Seiko Electronic Industries Co., Ltd.

Claims (1)

[Claims] Monolithic I consisting of control transistor and gate circuit
A switching regulator IC characterized in that a voltage output from an output terminal of a charge pump voltage converter including a capacitor and a switch transistor is used as a gate voltage of a control transistor of the switching regulator.