JPH0224275Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a pulse width conversion transmission device.

When transmitting an analog signal, it is converted into a pulse width signal by an integral type pulse width converter and then transmitted. The integral type pulse width converter has a noise removal function, and the pulse width signal is less susceptible to noise.
This is convenient because it can be easily converted into either analog or digital signals on the receiving side.

The converter that converts the analog signal into a pulse-width signal is located close to the source of the analog signal and connected to the signal receiver by a transmission line, so that the pulse-width converter operates with as little power as possible. It is desirable to do so. Recently, due to improvements in electronic circuits, the conversion circuit itself can now operate with sufficiently low power, but since the transmission signal requires a level of, for example, several tens of milliamps, it is difficult to output such a level. In order to generate a signal, the pulse width conversion circuit requires a considerable amount of power from the power source, and it has not been possible to reduce power consumption as desired.

An object of the present invention is to provide a pulse width conversion transmission device that reduces power consumption while maintaining a sufficient transmission output level.

The present invention is an integrator that integrates a continuously applied analog signal to be converted and a reference signal that is intermittently applied and has a value larger than the analog signal and has an opposite polarity. A comparator that discriminates and generates an output pulse when the polarity is determined, and a constant cycle clock given from the receiving side.
a flip-flop circuit that is set by a pulse, reset by an output pulse of the comparator, and controls the on/off of a reference signal in the integrator by its own output signal, having two coils of opposite polarity; 2 to intermittently apply voltage to the transformer and the two coils of this transformer.
The insulating circuit includes two transistors and two detecting means for separately detecting induced voltages from the other side in two coils of a transformer, and on one side of the insulating circuit, the comparator is connected to the base of the transistor. an isolated circuit in which the output pulses of the circuit are applied through a transmission line and the output signal of the detection means is applied as a set input signal to the flip-flop circuit through the transmission line, and on the other side a clock pulse is applied to the base of the transistor; and a pulse width conversion transmission device comprising a demodulation circuit including a flip-flop circuit set by a clock pulse and reset by an output pulse of the detection means on the other side of the isolation circuit. This has been achieved.

Hereinafter, the present invention will be explained in detail with reference to Examples. FIG. 1 is a conceptual block diagram of an embodiment of the present invention. In Figure 1, 1 is an integral type pulse width conversion circuit, 2 is a transmission line, 3 is a bidirectional isolation circuit, and 4 is a bidirectional isolation circuit.
is a demodulation circuit.

The pulse width conversion circuit 1 is a known one, and includes:
An integrator 11 integrates the difference between the analog signal Ex to be converted and the reference signal Es, a comparator 12 determines the polarity of the output signal, and the output signal of the comparator 12 is set by a clock with a constant period. and a flip-flop circuit 13 which is reset by the integrator 11 and controls the on/off of the reference signal Es of the integrator 11. In such a circuit 1, the analog signal Ex is converted into a pulse width output signal of the flip-flop circuit 13 by a known operation. A constant periodic clock pulse for setting the flip-flop circuit 13 is provided from the receiving side.

In the conventional device, the pulse width output signal of the flip-flop circuit 13 is transmitted, but in the present invention, the comparator 1 is transmitted instead.
2 output pulses are transmitted. The output pulse of comparator 12 has a much narrower pulse width than the output pulse of flip-flop circuit 13, so even if the amplitude is the same, its energy is much smaller. That is, pulse transmission with extremely low power consumption can be performed.

The output pulses of the comparator 12 are transmitted to the receiving side via the transmission line 2 and the insulation circuit 3.

The demodulation circuit 4 on the receiving side is constituted by a flip-flop circuit. This flip-flop circuit is a flip-flop circuit in the pulse width conversion circuit 1.
Similar to the flop circuit 13, a clock signal is connected to the S terminal.
A pulse is applied, and the output signal of the comparator 12 transmitted from the pulse width converter 1 is applied to the R terminal. Although the clock pulse generation circuit is omitted, it is provided on the receiving side. This flip-flop circuit converts the interval between the clock pulse and the output pulse of comparator 12 into a pulse width signal as shown in FIG. The pulse width signal is either smoothed into an analog signal or digitally measured and converted into a digital signal.

Here, the bidirectional insulation circuit 3 includes a transformer 31 having two coils with opposite polarities, and two transistors 321 and 322 that respectively connect and connect the power supply voltages supplied to the two coils of the transformer 31. , series circuits 331 and 332 of diodes and resistors that separate and detect the induced voltage from the other coil in the two coils, and polarity inverting circuits 341 and 342 for detection signals caused by these.
It consists of

In such an insulated circuit, transistor 3
21 is turned on and off by clock pulses, and transistor 322 is turned on and off by the output pulse of comparator 12. Here, when either transistor turns on, a voltage is induced in the other coil, this induced voltage is detected by a series circuit of a diode and a resistor connected to that coil, and the polarity is adjusted by an inverter. transmitted. Therefore, the clock pulses are transmitted from the receiving side to the pulse width converter 1 through this isolation circuit 3, and the output pulses of the pulse width converter 1 are provided to the receiving side. In this way, isolation of bidirectional signals can be achieved with a single isolation circuit.

Although the present invention has been described above with reference to preferred embodiments, the present invention may be implemented in various ways within the scope of the claims for utility model registration.

[Brief explanation of the drawing]

Figure 1 is a conceptual configuration diagram of an embodiment of the present invention;
The figure is an explanatory diagram of the operation of the apparatus of FIG. 1. 1...Pulse width conversion circuit, 2...Transmission line, 3...
...Isolation circuit, 4...Demodulation circuit.

Claims (1)

[Scope of utility model registration request] An integrator that integrates the analog signal to be converted that is continuously applied and a reference signal that is intermittently applied and has a value larger than this analog signal and has the opposite polarity.The polarity of the output signal of this integrator is determined and A comparator that generates an output pulse when the polarity is set, is set by a clock pulse of a constant period given from the receiving side, is reset by the output pulse of the comparator, and uses its own output signal to set the reference in the integrator. A flip-flop circuit that controls the on/off of signals, a transformer that has two coils with opposite polarities, two transistors that on/off apply voltage to the two coils of this transformer, and two coils of the transformer that are opposite to each other. Separately detect the induced voltages from 2
an insulating circuit including two detecting means, on one side of the insulating circuit, an output pulse of the comparator is applied to the base of a transistor through a transmission line, and an output signal of the detecting means is applied to the flip-flop via a transmission line; an isolated circuit which is applied as a set input signal to the flop circuit and on the other side a clock pulse applied to the base of the transistor; and an output of the detection means on the other side of said isolated circuit which is set by the clock pulse. A pulse width conversion transmission device comprising a demodulation circuit including a flip-flop circuit reset by a pulse.