KR100434290B1 - Circuit for Sensing Temperature of Electric Apparatus - Google Patents

Abstract

The present invention relates to a temperature sensing circuit of an electric device capable of detecting a temperature sensing signal of the number of A / D ports (input ports) of the microcomputer, that is, an A / D input signal, and a first method for sensing an external temperature. And first and second transistors in which a collector is connected to each output terminal of the first and second temperature sensing units in order to transmit output values of the second temperature sensing unit and the first and second temperature sensing units according to a control signal. First and second ports connected to respective bases of the first and second transistors to output a control signal for exclusively controlling the on / off of the first and second transistors; The first and second transistors are connected to emitters of the first and second transistors to selectively receive output values of the first or second temperature sensors according to mutually exclusive on / off of the first and second transistors. No. 3 may be configured to include a microcomputer consisting of a port, so improving the function of the product by allowing to detect more than one temperature through one of the input port detection signal.

Description

Circuit for Sensing Temperature of Electric Apparatus

The present invention relates to a temperature sensing circuit, and more particularly, to a temperature sensing circuit of an electrical device capable of sequentially inputting more than a number of A / D ports, that is, a plurality of A / D input signals through a few A / D ports. It is about.

In general, in order to control a predetermined function of an electric device, a plurality of temperature detections, such as temperature sensing of an IPM (Power Switching Device) or ambient temperature sensing of various loads, are required.

At this time, the sensed temperature detection signal is input to the corresponding A / D port of the microcomputer is determined to be a DC voltage level.

1 is a circuit diagram illustrating a temperature sensing circuit of an electric device according to the prior art. Referring to this, the temperature sensing circuit of the electric device according to the prior art will be described in detail as follows.

In general, a microcomputer embedded in an electric device has a limited number of A / D input ports among several ports, and the temperature sensing circuit of the electric device according to the prior art is configured by connecting one temperature sensing unit to one microcomputer input port.

For example, as illustrated, the first temperature sensing unit Th1 is connected to the third input port P3, and the second temperature sensing unit Th2 is connected to the fourth input port P4.

The sensing signals detected through the first and second temperature sensing units Th1 and Th2 are respectively input to the microcomputer through the third and fourth input ports P3 and P4.

In this case, the first and second temperature sensing units Th1 and Th2 use a thermistor, and an internal resistance value changes according to a change in ambient temperature, so that the changed internal resistance value and grounded first and second resistors ( Each DC voltage is applied through the third and fourth input ports P3 and P4 according to the distribution of R1 and R2.

The microcomputer determines the temperature level detected by the first and second temperature detectors Th1 and Th2 from the DC voltages applied to the third and fourth input ports P3 and P4.

As described above, the temperature sensing circuit of the electric device according to the prior art has a problem in that it cannot detect an A / D input signal more than the number of input ports of the microcomputer because only one input signal can be input to one input port. In general, since the number of input ports of the microcomputer is limited, there is a technical limitation in detecting the input signal beyond the number of input ports of the product.

The present invention has been made to solve the above problems according to the prior art, an object of the present invention is to detect the A / D input signal (temperature detection signal) more than the number of A / D port (input port) of the microcomputer. In order to provide a temperature sensing circuit of an electrical device.

1 is a circuit diagram showing a temperature sensing circuit of an electric apparatus according to the prior art

2 is a circuit diagram showing a temperature sensing circuit of an electric device according to the present invention;

Explanation of symbols for main parts of the drawings

P1, P2: first output port, second output port

P3: third input port

Th1, Th2: first temperature detector, second temperature detector

Tr1, Tr2: first transistor, second transistor

The temperature sensing circuit of the electric device according to the present invention includes the first and second temperature sensing units for sensing an external temperature, and the first and second temperature sensing units to transmit output values of the first and second temperature sensing units according to a control signal. First and second transistors having a collector connected to each output terminal of the temperature sensing unit, and outputting control signals for exclusively controlling on / off of the first and second transistors. In order to selectively receive the first and second ports connected to each base of the transistor and the output value of the first or second temperature sensing unit according to mutually exclusive on / off of the first and second transistors. It is characterized by including a microcomputer consisting of a third port connected to the emitter (Emitter) of the first and second transistors.

Hereinafter, a temperature sensing circuit of an electric device according to the present invention will be described with reference to the accompanying drawings.

2 is a circuit diagram showing a temperature sensing circuit of an electric device according to the present invention.

The temperature sensing circuit of the electric device according to the present invention detects two A / D input signals through one A / D port (input port) of the microcomputer.

As shown, the temperature sensing circuit of the electric device according to the present invention is the first and second temperature detection unit (Th1, Th2), the first and second temperature detection unit (Th1, Th2) for sensing the external temperature The collectors of the first and second transistors Tr1 and Tr2 are connected to the output terminals of the first and second temperature sensing units Th1 and Th2 in order to transfer the output values of the first and second temperature sensing units Th1 and Th2.

In addition, the first and second output ports P1 and P2 of the microcomputer output the control signals for controlling the on / off of the first and second transistors Tr1 and Tr2. The third input port P3 is connected to the bases of Tr1 and Tr2, respectively, and the third input port P3 is connected to the first and second transistors Tr1 and Tr2 in response to on / off. The first and second transistors Tr1 and Tr2 are connected to emitters to receive output values of Th1 and Th2.

In the temperature sensing circuit of the electric device according to the present invention connected and configured as described above, the first and second temperature sensing units Th1 and Th2 are used by thermistors, and the internal resistance value is changed according to the ambient temperature change. And outputs each voltage value according to the distribution of the changed internal resistance value and the first and second resistors R1 and R2.

The output values of the first and second temperature sensing units Th1 and Th2 are sequentially transferred to the third input port P3 of the microcomputer according to the on / off of the first and second transistors Tr1 and Tr2. Is entered.

In this case, on / off control of the first and second transistors Tr1 and Tr2 is performed according to control signals output from the first and second output ports P1 and P2 of the microcomputer. The operation of the first and second transistors Tr1 and Tr2 according to the control signals of the two output ports P1 and P2 will be described in detail with reference to Table 1 below.

First output port (P1) Second output port (P2) Third input port (P3) High Low Input of the output value of the first temperature detection unit Th1 Low High Input of the output value of the second temperature detection unit Th2

As shown in Table 1, the microcomputer alternately outputs control signals of the first and second output ports P1 and P2 at predetermined intervals.

In detail, when a high control signal is output from the first output port P1, the second output port P2 outputs a low control signal in association with the first transistor Tr1. Is turned on and the second transistor Tr2 is turned off.

At this time, when the first transistor Tr1 is turned on, the output value of the first temperature detector Th1 is input to the third input port P3.

Meanwhile, when the high control signal is output from the second output port P2, the second transistor Tr2 is turned on so that the output value of the second temperature sensing unit Th2 is input to the third input port P3. .

In the present invention, as described above, the microcomputer alternately outputs a control signal at predetermined intervals through the first and second output ports P1 and P2 so that the first and second transistors Tr1 and Tr2 are different. By controlling the on / off of), the output values of the first and second temperature sensing units Th1 and Th2 are sequentially input to the third input port P3.

The microcomputer receives the first and second temperature detectors Th1 and Th2 from the output values of the first and second temperature detectors Th1 and Th2 input through the third input port P3. Determine the sensed temperature level.

Therefore, since the output values of the first and second temperature detectors Th1 and Th2 are sequentially input to the third input port P3, two or more temperature detection signals may be input through one input port.

The temperature sensing circuit of the electric device according to the present invention as described above can improve the function of the product by enabling the sensing of the temperature detection signal, that is, the A / D input signal of the number of A / D ports (input ports) of the microcomputer. It has an effect.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (2)

First and second temperature sensing units for sensing an external temperature; First and second transistors in which a collector is connected to each output terminal of the first and second temperature sensing units in order to transmit output values of the first and second temperature sensing units according to a control signal; First and second ports connected to respective bases of the first and second transistors to output a control signal for exclusively controlling the on / off of the first and second transistors; A third port connected to emitters of the first and second transistors to selectively receive output values of the first or second temperature sensing units according to mutually exclusive on / off of the first and second transistors Temperature sensing circuit of an electric device, characterized in that configured to include a microcomputer. The method of claim 1, The first and second transistors The second transistor is turned off when the first transistor is turned on according to mutually exclusive control signals outputted through the first and second ports of the microcomputer to selectively transfer output values of the first and second temperature sensors. And when the first transistor is turned off, the second transistor is turned on.