JPS6244815A - Constant voltage power supply device - Google Patents

Abstract

PURPOSE:To set up optionally a detecting level by setting up an excess voltage detecting level in an excess voltage detecting level setting register based on an external signal. CONSTITUTION:A constant voltage power supply device is constituted of a constant voltage circuit (a), an excess voltage protecting circuit (p), an excess voltage detecting circuit (b), a D/A conversion circuit (c), and an excess voltage detecting level setting register (d). The value of the register (d) is set up by an externally set signal (s) and the digital value of the register (d) is converted into an analog value, which is inputted to the circuit (b). Consequently, the circuit (b) compares a constant voltage output dc2 with an excess voltage comparing voltage Vref outputted from the D/A conversion circuit (c), and when Vref<dc2, the excess voltage protecting circuit (p) is actuated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an overvoltage detection function of a constant voltage power supply used in an information processing device, and in particular, a method for arbitrarily setting the overvoltage detection level of a constant voltage power supply using an external signal. This invention relates to a constant voltage power supply device that has the following functions.

[Prior art] Conventionally, the overvoltage detection level of this type of constant voltage power supply device is
It was a fixed setting during manufacturing and inspection.

In addition, since the overvoltage detection level is fixed, it is not possible to perform dynamic function tests using diagnostic programs, etc. Conventionally, the overvoltage detection function was checked by increasing the output voltage of the constant voltage power supply. was.

[Problems to be solved] Since the overvoltage detection level of the conventional constant voltage power supply device described above is fixedly set, it is not possible to perform dynamic function tests using diagnostic programs, etc.; Since the output voltage of the power supply device is increased to check the overvoltage detection function, there is a drawback that it has an adverse effect on the logic circuits etc. that are the load.

[Means for Solving Problems] The present invention has been made by focusing on the above-mentioned conventional problems, and allows the overvoltage detection level to be set arbitrarily.

The present invention aims to provide a constant voltage power supply that does not adversely affect logic circuits, etc., to confirm the overvoltage detection function as in the past.

To this end, the present invention provides means for holding the overvoltage detection level of a constant voltage power supply used in an information processing device in a register, and means for setting the overvoltage detection level in the register for holding the overvoltage detection level using an external signal. a voltage regulator having: a means for converting a register value for holding the overvoltage detection level into an analog voltage; and a means for comparing the output voltage value of the voltage regulator with the analog converted voltage value of the register for holding the overvoltage detection level. It provides a power supply device.

[Example] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a constant voltage power supply device according to an embodiment of the present invention. In the figure, a is a constant voltage circuit, p is an overvoltage protection circuit, b is an overvoltage detection circuit, C is a D/A conversion circuit, d is a register for setting an overvoltage detection level, and S is an overvoltage detection level setting signal.

The constant voltage circuit a performs constant voltage control on the input voltage del and outputs a constant voltage dc7, and the overvoltage protection circuit p is controlled by the overvoltage detection circuit 1. When overvoltage is detected, the constant voltage output dC3 is cut off, and normally the constant voltage output dc7 is output as is as the constant voltage 111 power dc3.

The value of the overvoltage detection level setting register d is set by an external setting signal S, and the digital value of the overvoltage detection level setting register d is converted into an analog value by the D/A converter circuit C. is input.

The overvoltage detection circuit compares the constant voltage output dc2 with the overvoltage comparison voltage Vref of the D/A conversion circuit C, and
<dc2, it operates to operate the overvoltage protection circuit p.

Therefore, the overvoltage detection level can be set arbitrarily.

[Effects of the Invention] As explained above, the present invention provides a means for holding an overvoltage detection level of a constant voltage power supply used in an information processing device in a register, and a means for holding the overvoltage detection level holding register by an external signal. A means for setting an overvoltage detection level, a means for converting a register value for holding the overvoltage detection level into an analog voltage, and a comparison between the output voltage value of the voltage regulator and the analog converted voltage value of the register for holding the overvoltage detection level. Since the constant voltage power supply device has a means for
This has the effect of preventing an adverse effect on logic circuits and the like for checking overvoltage functions as in the past.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of a constant voltage power supply device according to an embodiment of the present invention. dcl: Input voltage dc2, dc3: Constant voltage output a: Constant voltage circuit p: Overvoltage protection circuit b: Overvoltage detection circuit c: D/A conversion circuit d: Overvoltage detection level setting register S: Overvoltage detection level setting signal

Claims (1)

[Claims] means for holding an overvoltage detection level of a constant voltage power supply used in an information processing device in a register; means for setting the overvoltage detection level in the register for holding the overvoltage detection level using an external signal; and means for holding the overvoltage detection level. A constant voltage power supply device comprising means for converting a register value of the constant voltage device into an analog voltage, and means for comparing an output voltage value of the constant voltage device with an analog converted voltage value of a register for holding an overvoltage detection level.