JPH0683026B2 - Electronics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an electronic device.

(B) Conventional Technology Conventionally, an electronic device such as a synthesizer receiver that performs a sweep operation by changing a frequency division ratio of a frequency divider is known.

This type of synthesizer receiver is generally constructed as shown in FIG.

In FIG. 3, (1) is an antenna, (2) is a high-frequency amplifier circuit that selectively amplifies the high-frequency signal from the antenna (1), and (3) is a local oscillator circuit composed of a PLL circuit, which is a voltage-controlled oscillator circuit (VCO). ) (4), a programmable frequency divider (5) that divides the oscillation signal from this VCO (4) by N (N is an integer), and a signal divided by this programmable frequency divider (5) A phase comparator (7) that compares the oscillation signal from the reference oscillator (6) and the phase difference signal from this phase comparator (7) is converted into a DC voltage and supplied to the VCO (4) as a control voltage. It is composed of a filter circuit (8). (9) is a mixing circuit for mixing the high frequency signal from the high frequency amplifier circuit (2) and the oscillation signal from the local oscillation circuit (3) and converting it to an intermediate frequency signal, and (10) is an intermediate circuit for amplifying the intermediate frequency signal. Frequency amplification circuit, (11) detection circuit, (12) stereo demodulation circuit that demodulates the left and right stereo signals from the detection output signal (composite signal), (13) and (14) are low-level stereo signal lines. Frequency amplifier circuit, (15)
(16) is a speaker driven by each of the low-frequency amplifier circuits (13) and (14), (17) is a signal detection circuit that outputs a detection signal (So) when a signal of a predetermined level or more is received, ( 18)
A controller for controlling the frequency division ratio of at least the programmable frequency divider (5), and a detection signal input terminal (19) to which the detection signal (So) of the signal detection circuit (17) is applied.
The controller (18) is set to the sweep stop mode when the detection signal (So) is applied.

(C) Problems to be solved by the invention In this type of synthesizer receiver, the controller composed of a microcomputer is set to a low power consumption state (that is, a backup state) at the time of a power failure, and the external large-capacity capacitor is provided inside the controller. It holds the stored tuning data.

By the way, the setting of the controller to the backup state is generally made based on the signal supply to the power failure detection terminal of the controller, but since the terminal is required only during a power failure, a dedicated terminal should be provided in this way. Was inefficient in terms of effective use of terminals.

(D) Means for Solving Problems In view of the above problems, a power input terminal to which operating power is supplied via a power switch, a stereo reception state when energized, and an L level (or H level) at power failure Each circuit has a signal output terminal that becomes H level (or L level) in a stereo non-reception state when energized, and a circuit for executing the operation of the device, a backup power input terminal, and a voltage from the operation power supply function as a power switch. An inhibit terminal supplied through the controller, a controller having a signal input terminal to which a signal from a signal output terminal of the circuit and a voltage from a backup power source are supplied, and an inhibit terminal of the controller. Based on the state of the signal supplied and the state of the signal supplied from the circuit to the signal input terminal of the controller, An electronic device characterized in that the controller is set to a backup state.

(E) Operation According to the present invention, it is determined whether there is a power failure based on a signal supplied from a circuit for executing the operation of the device, for example, a stereo display signal, and it is determined that the power is in a power failure state. If so, set the controller to backup state.

(F) Embodiment FIG. 1 shows an embodiment of the present invention. In the figure, (20) is a controller, (21) is a controller (2
0) stereo display signal input terminal, (22) inhibit terminal, when the signal applied to this terminal is L level,
The controller (20) is set to the inhibit state.
(23) is a backup power input terminal, (24) is a stereo demodulation circuit provided in the receiving section (25), and the stereo display signal output terminal (26) is connected to the stereo display signal input terminal (21) of the controller (20). , The power input terminals (27) are connected to the power line (28), respectively. (29) is a power switch, (30) is a large-capacity capacitor for backup, (3
Reference numeral 1 is a backflow prevention diode, (32) and (33) are bias resistors for the inhibit terminal (22), and (34) is a bias resistor for the stereo display signal input terminal (21). The power source (+ B2) is a backup power source. Next, the operation will be described with reference to the flowchart of FIG.

When the power switch (29) is turned off and the input to the inhibit terminal (22) of the controller (20) becomes L level,
The controller (20) controls the time t1 (eg 1
Second), the state of the stereo display signal supplied to the stereo display signal input terminal (21) is judged (step 3).

That is, when the power switch (29) is turned off, the stereo demodulation circuit (24) does not operate and the stereo display signal is not output. However, if there is no power failure at this time, the backup power supply (+ B2) passes through the resistor (34). Controller (20)
Since it is supplied to the stereo display signal input terminal (21) of
The above operation is repeated. During such operation, when the power switch (29) is turned on and the input to the inhibit terminal (22) becomes H level, the controller (20) is set to the normal radio operating state.

On the other hand, if there is a power failure, the input to the stereo display signal input terminal (21) of the controller (20) is at L level (first predetermined level), so the process proceeds to step 4 and the clock circuit (not shown) It is determined whether or not the time t2 (for example, one minute) is timed. If not, then in step 5, it is determined whether or not the input to the inhibit terminal (22) is at the H level.

At this time, the input to the inhibit terminal (22) is H
If it is inverted to the level, it returns to the initial state, and if it is kept at the L level, it returns to step 4, and the time counting circuit restarts the time t.
It is determined whether or not 2 is timed.

Further, when the time t2 is timed by the time counting circuit, the controller (20) is set to the backup state.

The standby at time t1 in step 2 is when the stereo demodulation circuit (24) outputs the stereo display signal (L level) (first predetermined level) indicating that stereo reception is in progress, This is to prevent malfunction if 29) is turned off.

In the above embodiment, the case where the power failure state is detected using the stereo display signal has been described, but it may be detected using, for example, a signal indicating the carrier level.

It can also be applied to a tuner with a clock, in which case the clock operating state is set when it is determined in step 3 that the input to the stereo display signal input terminal (21) is at the H level (second predetermined level). It should be done. Furthermore, it can be applied not only to the receiver but also to other electronic devices.

(G) Effect of the Invention According to the present invention, a circuit for executing the operation of the device,
An electronic device including a controller for controlling the operation of this circuit, wherein the controller is set to a backup state based on the state of a signal supplied from the circuit to the controller, so that a power failure is exceptional. It is possible to reliably detect a power failure state without providing a detection terminal on the controller.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a flow chart diagram, and FIG. 3 is a diagram showing a configuration of a general synthesizer receiver. (20): Controller, (21): Stereo display signal input terminal, (22): Inhibit terminal, (24): Stereo demodulation circuit, (29): Power switch.

Claims (1)

[Claims] 1. A power input terminal to which operating power is supplied via a power switch, a stereo reception state when energized, and an L level (or H level) when a power failure occurs, and an H level (or L level) in a stereo non-reception state when energized. Circuit) for executing the operation of the device, a backup power supply input terminal, an inhibit terminal to which the voltage from the operating power supply is supplied through a power switch, and a signal output of the circuit. An electronic device comprising a controller having a signal input terminal to which a signal from a terminal and a voltage from a backup power source are supplied, the state of a signal supplied to an inhibit terminal of the controller, and the controller from the circuit. Set the controller to the backup state based on the state of the signal supplied to the signal input terminal. An electronic apparatus characterized in that the.