JPS62122425A - transmitting device - Google Patents

Abstract

PURPOSE:To reduce the power consumption by providing a switching means being closed between a transmission circuit and a power supply circuit just before the start of the transmission of the transmission circuit until juts its end so as to supply power to the transmission circuit. CONSTITUTION:A switching circuit 4 consists of the 1st, 2nd transistors (TRs) Q1, Q2 constituting a current amplifier circuit and a resistor R1 connected to the base and emitter of the 1st TR Q1. A processing circuit 8 gives a control signal to a line l2. The processing circuit 8 gives a high level signal at a time t1 to a base of the 2nd TR Q2 via the line l2, a comparatively large bias current flows to a collector of the 3rd TR Q3 via the 1st TR Q1 and a transmission circuit 2 is brought into the transmission enable state. When a period W2 elapses from the end time t3 of the transmission of a transmission signal from the processing circuit 8, the processing circuit 8 gives a low level signal to the line l2, the TRs Q1, Q2 are cut off and the supply of the bias current to the transmission circuit 2 is stopped. Thus, the waste of the power consumption is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transmitting device that is advantageously used for transmitting signals over a transmission path such as a coaxial cable.

BACKGROUND ART Conventionally, in order to transmit pulse signals, for example, to a transmission path such as a coaxial cable, a drive circuit including a resistor and a transistor has been connected between power supply lines. However, as the transmission speed of the pulse signal increases, the power consumption of the drive circuit increases, and the power loss when the transistor is turned on increases.

Furthermore, the structure of the drive circuit itself requires the use of components with large power dissipation, which is disadvantageous for high-density packaging.

Problems to be Solved by the Invention An object of the present invention is to solve the above-mentioned technical problems, eliminate wasteful power consumption, and provide a transmitting device that can transmit signals at high speed. be.

Means for Solving the Problems The present invention provides: a transmitting circuit for deriving a signal; a power supply circuit; and a transmitting circuit interposed between the transmitting circuit and the power supply circuit, and starting immediately before the start of a transmitting operation by the transmitting circuit. 1. A transmitting device characterized by comprising: switching means that is conductive until immediately after the transmitting operation of the transmitting device ends, and supplies power from the power supply circuit to the transmitting circuit.

According to the present invention, by energizing the transmitting circuit immediately before the transmitting circuit starts the transmitting operation, it is possible to prevent the initial part of signal transmission from being lost (transmission can be performed reliably). Also, by de-energizing the transmission circuit immediately after the transmission operation by the transmission circuit is completed, power consumption can be saved.

Embodiment tjIJ1 FIG. 1 is an electrical circuit diagram of an embodiment of the present invention. Transmitting device according to the invention r! 11 is basically interposed between the transmitting circuit 2 that derives the signal, the power supply circuit 3, the transmission image w12, and the power supply circuit 3, and starts the transmission operation of the transmitting circuit 2 immediately before the transmitting operation starts by the transmitting circuit 2. It includes a switching circuit 4 that is conductive until just before the end of the transmission operation and supplies power from the power supply circuit 3 to the transmission circuit 2.

A switching circuit 4 is interposed in the middle of the power supply line 1. Sui nching times! &4 includes first and second transistors Q1 and Q2 forming a current amplification circuit, and a resistor R1 connected between the base and the bimitter of the first transistor Q1. The left side of the fjS2 trunk transistor Q2 is connected to the base of the transistor Q1 via a resistor R2, and the emitter side is grounded. The base of the second transistor Q2 is connected to the line J! 2 to a processing circuit 8 realized by a microcomputer or the like. The processing circuit 8 derives a pulse signal (hereinafter referred to as a control signal) shown in the fjS2 diagram (1) on the line 2.

The transmitting circuit 2 includes a series circuit of a resistor R3 and a third transistor Q3 interposed between the power line 11 and the ground side, and the power line! A connection point 7 between the resistor R3 and the third transistor Q3, which includes a series circuit of the resistor R4 and the fourth transistor Q4, is connected to the base of the fourth transistor Q4. Ru. The third transistor Q3 operates as a preceding stage drive circuit of the fourth transistor Q4. The resistor R3 has a small resistance value, which allows the third and tJS4) transistor Q3 to be described later.
．． Q4 high-speed operation can be achieved.

The base of the third transistor Q3 is connected to the resistor R5 and the line ! 3 to the processing circuit 8.

The processing circuit 8 is a line! 3, a pulse signal (hereinafter referred to as a transmission signal) shown in FIG. 2 (2) is derived.

The transmission signal from the transmission circuit 2 is transmitted to the transmission path 6 via the protection circuit 5. The protection circuit 5 includes a diode D1 interposed in the middle of the center conductor 9 and a connection point 1 of the center conductor 9.
0 and the ground side, and a series circuit of one or more (two in this embodiment) diodes D2. The diodes Di and D2 serve to protect the transmitter circuit 2 from high-level surges from the transmission path 6, undesired overshoots, and undersineats.

The processing circuit 8 sends the transmission signal shown in FIG. 2(2) to the line 73 for a period W3 from time t2 to time t3. The processing circuit 8 also has a line! 2, sends the control signal shown in m2 diagram (1). This control signal is at a high level only during a period from time t1, which is a predetermined period W1 before time t2, to time t4, which is a predetermined period W2 after time t3.

The periods Wl and W2 are, for example, 10 μSee, so that the transmitting circuit 2 can maintain the time t at which the transmitting signal is being sent.
The transmission signal can be reliably transmitted to the center conductor 9 with stable operation only during the period W3 from 2 to t3.

Hereinafter, the operating state of the transmitting device 1 will be explained with reference to the tlS3 diagram. First, when the power source 3 is turned on, the process moves from step n1 to step n2. Next, the process moves to step n3, and the processing circuit 8 sets line 3 to high level, LINE! At the 0th step n, initialization is performed with 2 set to low level.
4, it is determined whether the mode is transmission mode. If it is determined that it is not in transmission mode, proceed to step n3.
Returning to step n5, if it is determined that the mode is transmission mode, the process moves to step n5. The processing circuit 8 provides a high level signal to the base of the second transistor Q2 via the line 72 at time t1. In this case, the transistor Q1 and the second transistor Q2 cooperate to perform a current amplification function, and a relatively large bias current flows through the first transistor Q1 to the left of the third transistor Q3. As a result, the transmitting circuit 2 becomes ready for transmitting operation.

Next, the process moves to step n6, where the timer in the processing circuit 8 is set.Next, the process moves to step n7,
It is determined whether a period W1 has elapsed since time t1,
When the period W1 has elapsed, the process moves to step n8, and the processing circuit 8 sends a transmission signal to the third transistor Q3 via the line 13 as shown in FIG. 2(2). This transmission signal is transmitted to the center conductor 9 by the current amplification effect of m4) transistor Q4. Next, the process moves to step n9, and it is determined whether the output of the transmission signal from the processing circuit 8 has been completed. If it is determined that the process has not ended, the process returns to step n8, and if it is determined that the process has ended, the process proceeds to step n9, where a timer in the processing circuit 8 is set.

Next, the process moves to step nil, where it is determined whether a period W2 has elapsed since the end time L3 of the transmission signal from the processing circuit 8. When it is determined that the time has not elapsed, the process returns to step nlo, and when it is determined that the time has elapsed, the process moves to step n12, where the processing circuit 8 supplies a low level signal to the line no.

This allows the first and fj & 2) Lannostar Ql
.

Q2 is cut off, the supply of bias current to the transmitting circuit 2 is stopped, and then the process moves to step n13 to end the operation.

In this way, by setting the transmitting circuit 2 to the transmitting state immediately before transmitting the transmitting signal, and releasing the transmitting possible state of the transmitting circuit 2 immediately after the transmitting signal finishes leaving the transmitting signal, the consumption can be reduced. By interposing the switching circuit 4 constituting the current amplification circuit in the middle of the power supply line 71, it is possible to reduce waste of power.
It becomes possible to supply bias current to the transmitting circuit 8 using a control signal from the processing circuit 8 with a relatively small current.

In the embodiment described above, the transmission signal is transmitted through the wired transmission path 6, but a configuration may also be adopted in which the transmission signal modulated by a carrier wave is transmitted wirelessly.

Although the transmission signal has a pulse waveform in the above embodiment, it is not limited to this, and may be an analog waveform such as a video signal.

Effects As described above, according to the present invention, the transmitting circuit is energized with power immediately before the transmitting circuit starts the transmitting operation, and immediately after the transmitting circuit finishes the transmitting operation, the transmitting circuit is powered up. By using only one signal, it is possible to transmit signals without wasting power consumption.

[Brief explanation of drawings]

Figure rjS1 is an electric circuit diagram of an embodiment of the present invention, and Figure 2 (
1) is a waveform diagram of the control signal, FIG. 2 (2) is a waveform diagram of the transmission A/J compensation signal, and FIG.
It is 0-chier F. DESCRIPTION OF SYMBOLS 1... Transmission device, 2... Transmission circuit, 3... Power supply circuit, 4... Switching circuit, 5... Protection circuit, 6
...Transmission path, 8...Processing circuit agent Patent attorney Number of strokes Keiichi Figure 3

Claims (1)

[Scope of Claims] A transmitting circuit that derives a signal, a power supply circuit, and a circuit provided between the transmitting circuit and the power supply circuit, from immediately before the transmitting circuit starts transmitting operation to immediately after the transmitting circuit finishes transmitting operation. A transmitting device comprising: switching means that is electrically connected to supply power from a power supply circuit to a transmitting circuit.