JPH01190130A - Booster power supply circuit - Google Patents

Abstract

PURPOSE:To easily take a countermeasure at the time of generating a fault by detecting a current supplying from a power supply section to an antenna cable, and displaying the state of short-circuit, open wire and normality of the power supply path depending on the detected current. CONSTITUTION:A power supply section 7 supplies a current to an antenna cable and a current detection circuit 13 via a current detection circuit 10. When a comparator 14a of the circuit 13 detects a current over the normal current, the comparator gives an output, in the detection of a current in the range of normal current, a comparator 14b generates an output, in case of the detection of a current below the lower limit of the normal current, a comparator 14c gives an output respectively. The output of the comparator 14a turns on a TR Q2 of a display circuit 16 to allow the LED 1 to cause a short-circuit display, the output of the comparators 14b, 14c turns on TRs Q3, Q4 to light LEDs 2, 3 thereby displaying normal/open wire display. Thus, the countermeasure at the occurrence of fault is easily taken.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a booster power supply circuit that supplies power to a booster for a television antenna.

[Prior Art] Fig. 3 shows an antenna system such as a public listening system, in which a distributor 3 is connected to the antenna 1 via a booster 2, and a series unit 5 is connected to the distributed antenna cables 4m and 4b. Insert and connect multiple . The antenna cable 4a side is used as a current passing path, and the series unit 5 to which the booster power supply circuit 6 is connected is an input branch output current passing type. The unit 5 is of an input/output current passing type, and power is supplied to the booster 2 from a booster power supply circuit 6.

[Try to solve the invention! llN1 In the conventional booster power supply circuit 6, there was a wiring mistake during construction, and even if a short circuit or disconnection occurred in the power supply path, there was no means to detect and display this, and it was unclear how to deal with it.

The present invention was made in view of these problems, and its purpose is to detect and display an abnormality in the power supply, and to detect and display an abnormality in the power supply when a short circuit occurs in the supply path. The object of the invention is to provide a booster power supply circuit that automatically performs current limiting for circuit protection.

[Means for Solving Problem W] The present invention provides a power supply unit including a constant current circuit that limits the supplied current, a current amount detection circuit that detects the amount of supplied current, and a current detected by the current amount detection circuit. The antenna is equipped with a display circuit that displays disconnection, normality, and short circuit according to the amount of wire disconnection, normality, and short circuit using corresponding display elements, and current is caused to flow from the power supply section to the antenna cable through the high frequency cutoff circuit.

[Operation] If the amount of supplied current is within a range that is considered normal as the current supplied to the booster, the display circuit drives a display element that indicates normality with the detection output of the current amount detection circuit. If a disconnection occurs in the supply path, including the antenna cable, the current detected by the current detection circuit will be smaller than the lower limit of the normal range because the supply current will not flow, and the disconnection will be handled by a detection output corresponding to this current amount. The display circuit drives the display element to indicate that a disconnection has occurred.

Furthermore, if a short circuit occurs in the supply path including the antenna cable, the supply current will increase, and this increase in current will be limited to the current value determined by the constant current circuit of the power supply section, but there is an upper limit to the amount of current that is allowed as normal. Therefore, the display circuit drives a display element provided in response to the short circuit based on the detection output of the current detection circuit corresponding to this increase in current, thereby indicating that a short circuit has occurred.

[Embodiment] FIG. 1 shows a circuit of an embodiment, in which the power supply section 7 includes a transformer Tr that steps down the commercial power supply voltage, and a full-wave rectifier Br.
and a constant current circuit 8 consisting of a transistor Q for current control, etc., and the output is sent to a current transformer C of the current detection circuit 10.
It is connected to the connection terminal 11 via T and an inductance element of the high frequency cutoff circuit 9.

The connection terminal 11 is a terminal for connecting to the input branch output current passing type series unit 5 which is inserted into the antenna cable 4a in the system shown in Fig. VI3.
A current is applied to the antenna 1 to supply power to the booster 2 which is connected to the antenna 1.

A TV connection terminal 12 is commonly connected to this connection terminal 11 via a DC cutoff capacitor C2.

The Takaoka a disconnection circuit 9 is composed of an inductance element and a capacitor C1, and blocks the high frequency input through the connection terminal 11 from inputting to the power supply g7 (1m).

The current detection circuit 10 is for detecting the supplied current by the current transformer CT, and rectifies the secondary output of the current transformer CT with a diode D, smoothes it with a capacitor C3 and a resistor R1, and converts the output into a current amount. Connect to the detection circuit 13.

The current amount detection circuit 13 is a circuit for detecting the amount of current,
It is composed of three comparators 14m, 14b, 14c, AND date A, , A2, inverter ll-I2, etc., and stabilizes the output voltage of the step-down transformer Tr to a constant voltage. Resistance R2-R
3. Comparator 14a outputs each divided voltage by R4.
, 14b, and 14c, and the comparator 14a generates an output when it detects the amount of current that flows when the supply path is short-circuited, that is, the current 1 that is higher than the current 1 that is allowed as normal, and the comparator 14b outputs an output when it detects a current 1 that is higher than the current 1 that is allowed as normal. The comparator 14c generates an output when it detects an amount of current that is greater than the lower limit of the range that can be considered normal, and the comparator 14c generates a detected output when the amount of current that is supplied is smaller than the lower limit. . 7nd date A inputs the output of comparator 14b and the inverted output of comparator 14a, uses the date output as a normal state detection signal, and does not generate this normal state detection signal if there is an output of comparator 14m. , AND date A2 inputs the inverted output of the comparator 14b and the output of the comparator 14c, uses the date output as a disconnection state detection signal, and does not generate this disconnection state detection signal if there is an output of the comparator 14b. , the comparator 14a uses its output as a short-circuit state detection signal. These state detection signals become display drive signals for the display circuit 16.

The display circuit 16 includes three light emitting diodes L as display elements.
EDI, LED2. Equipped with LED3, each light emitting diode LEDI, LED2. LED3 has a transistor Q2 connected in series through resistors Rs and R-R2, respectively.
．． Q3. When Q is turned on, a light emitting current flows and light is emitted.

The transistor Q2 is connected to the output of the comparator 14a via a resistor R, and is turned on by the output of the comparator 14a to cause the light emitting diode LEDI to emit light to indicate a short circuit.The transistor Q2 is the date output of A+. is connected through a resistor R1, and is turned on by the date output of ANDA, causing the light emitting diode LED2 to emit light and performing normal display. Transistor Q4 is connected to the date output of 7nd date A2 via a resistor R1°, and is turned on by the date output of 7nd date A2 to turn on the light emitting diode LED3.
lights up to indicate a disconnection.

The neon tube 17 is a power indicator light, and lights up while the power plug 18 is connected to a commercial power outlet.

Figure 2 shows the circuit of this embodiment! ! It shows the appearance of the
The cable 19.20 shown is the cable connected to the A terminal 11.12 and connected to the series unit 5, a television (not shown).

[Effects of the Invention] As described above, the present invention includes a power supply section including a constant current circuit that limits the supplied current, a current amount detection circuit that detects the amount of supplied current, and a current amount detected by the current amount detection circuit. The display circuit is equipped with a display circuit that displays disconnection, normality, and short circuit depending on the state of the wire, using corresponding display elements. It is possible to detect and display short circuits, disconnections, and normal conditions, making it easy to take measures when an abnormality occurs.Moreover, in the event of a short circuit, current is automatically limited using a constant current circuit to protect the circuit. effective.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is an external perspective view of a device incorporating the same, and FIG. 3 is a configuration diagram of a public listening system. 7... Power supply unit, 8... Constant current circuit, 9... High frequency cutoff circuit, 11... Current detection circuit, 13... Current amount detection circuit, 16... Display circuit, LEDI, LED
2°LED3: A light emitting diode.

Claims (1)

[Claims] (1) A power supply unit equipped with a constant current circuit that limits the supplied current, a current amount detection circuit that detects the amount of supplied current, and a disconnection, normal, or short circuit according to the amount of current detected by the current amount detection circuit. What is claimed is: 1. A booster power supply circuit comprising: a display circuit that displays information using display elements provided correspondingly to each display circuit; and a booster power supply circuit configured to cause current to flow from a power supply section to an antenna cable through a high frequency cutoff circuit.