JPH02148207A - Boosting circuit - Google Patents

Abstract

PURPOSE:To eliminate an unnecessary radiation caused by an oscillation, and also, to contrive the simplification and the miniaturization of the constitution by executing the boosting in terms of DC by an optical system constituted of a light emitting element and an optical power generating element. CONSTITUTION:An irradiation light from a light emission diode D4 is photodetected by plural photodiodes D5, a boosting voltage Vout corresponding to its light quantum is generated between both ends of a photodiode array 19, and this boosting voltage Vout is brought to voltage division to 1/N and fetched from a slider 22a of a variable resistor 22. A voltage - current conversion amplifier 21 controls a current flowing to the light emission diode D4 so that a level difference between the 1/N divided voltage of the boosting voltage Vout and a reference voltage Vref is eliminated, and the boosting voltage Vout of Vout = N . Vref is obtained between both the ends of the photodiode array 19. Since boosting is executed in terms of DC by an optical system, an unnecessary radiation caused by an oscillation is eliminated, and also, the constitution can also be simplified and miniaturized.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a booster circuit suitable for use in, for example, a portable FM/AM receiver or an electronic tuning circuit of a television receiver. Regarding improvements.

(Prior Art) As is well known, the above-mentioned booster circuit has conventionally been a DC (direct current) circuit that combines an oscillation circuit and a step-up transformer.
- A boosted voltage is obtained by a DC converter. A control voltage to be supplied to the variable capacitance diode of the electronic tuning path is obtained from this boosted voltage.

FIG. 4 shows such a conventional booster circuit. That is, the output voltage v1 of the DC voltage source 11 drives the oscillation circuit 12 including the transistor Q1. A boosted voltage is obtained by converting the output of this oscillation circuit I2 into a DC voltage via a boosting transformer 13 in a smoothing circuit 14 made up of a diode D1 and a capacitor C1.

In this case, in the oscillation circuit 12, the amplitude level of the oscillation output is always stabilized by the action of the Zener diode Dz, and as a result, the boosted voltage is also stabilized.

Then, the boosted voltage is divided by a variable resistor 15,
After the ripple component is removed by capacitor C2, resistor R
Variable capacitance diodes D2.L and R2 forming the resonance circuits 18 and 17, respectively. Subjected to D3 bias.

However, since the conventional booster circuit as described above uses the oscillation circuit 12, there is a problem in that unnecessary radiation from the oscillation circuit 12 adversely affects the receiver or the image receiver. Further, since many circuit components such as the step-up transformer 13, resistors, and capacitors are used, the configuration becomes complicated and is not suitable for miniaturization.

(Problems to be Solved by the Invention) As described above, conventional booster circuits have problems in that unnecessary radiation caused by oscillation adversely affects other circuits and is economically disadvantageous due to the complicated configuration. are doing.

Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an extremely good booster circuit that does not generate unnecessary radiation, has a simple structure, and is suitable for downsizing.

[Configuration of the Invention (Means for Solving the Problems) A booster circuit according to the present invention includes a light emitting element driven by a DC voltage source, and a level corresponding to the amount of light that is received from the light emitting element. A device comprising a photovoltaic element that generates a direct current voltage, and configured to compare a signal corresponding to the output of the photovoltaic element with a reference signal, and control the amount of light emitted by the light emitting element so that the difference component is eliminated. It is.

(Function) According to the above-mentioned configuration, since the optical system including the light-emitting element and the photovoltaic element boosts the voltage in a direct current manner, unnecessary radiation caused by oscillation as in the conventional case is eliminated, and the configuration is also simplified. It becomes simple and can be made smaller.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In Figure 1, 18 is a photocoupler,
For example, a light emitting diode D4, such as a Ca A, Q As infrared light emitting diode, and a plurality of photodiodes D5.
A photodiode array 19 formed by connecting D5 . . . in series is tightly coupled optically.

Among these, the anode of the light emitting diode D4 is grounded via a DC voltage source 20 (for example, about 3V) with the illustrated polarity, and the cathode is connected to the output terminal of a voltage-current conversion amplifier (hereinafter referred to as GM amplifier) 21. .

Further, the cathode of the photodiode array 19 is grounded, and the anode is grounded via the variable resistor 22. The slider 22a of this variable resistor 22 is connected to the gm
It is connected to the negative input terminal of the amplifier 21. In addition, the positive input terminal + of the 20gm amplifier 21 has the polarity shown in the j! It is grounded via the Mulberry voltage source 23.

Furthermore, the anode of the photodiode array 19 is grounded via a capacitor C3 for ripple removal, and is connected to variable capacity diodes DB and D7 after passing through resistors (for example, 100Ω or more) R3 and R4, respectively. It is connected to a resonant circuit 24, 25 consisting of DC blocking capacitors C4 and C5 and coils LL and L2.

The operation of the above configuration will be described below. First, the irradiated light from the light emitting diode D4 is transmitted to the photodiode D5. D5 .

This boosted voltage V out is applied to the slider 2 of the variable resistor 22.
The voltage is divided to 1/H from 2a and taken out, and the 2m amplifier 2
1 is applied to the negative input terminal 1 of 1.

Here, the 2m amplifier 21 is 1/1 of the boosted voltage V out.
The H divided voltage and the reference voltage V rer outputted from the reference voltage source 23 are compared in level, and the current flowing through the light emitting diode D4 is controlled so that the level difference disappears. For example, if Vout/N<Vref', the output current of the 2m amplifier 21 increases, and the current flowing through the light emitting diode D4 is increased.

Then, the amount of light irradiated by the light emitting diode D4 increases, and as a result, the boosted voltage VOut generated from the photodiode array 19 increases, and is about to be stabilized under the condition of Vout/N'=Vre['.

In other words, a boosted voltage Vout of Vout-N-Vref' is obtained between both ends of the photodiode array 19, and this boosted voltage Vout operates the slider 22a of the variable resistor 22. It can be changed by doing this.

Then, the boosted voltage Vout generated as described above
After the ripple component is removed by the capacitor C3, the capacitors are connected to the variable capacitance diodes D6. It is applied to the bias of D7.

According to the configuration of the above embodiment, the light emitting diode D4
Since the voltage is boosted in a direct current manner by an optical system using a photodiode array 19 and a photodiode array 19, unnecessary radiation caused by oscillation as in the conventional method is eliminated, and the configuration is simplified and miniaturization can be achieved. .

Here, if the resonant circuit 24 is used as a local oscillation circuit and the resonant circuit 25 is used as a bandpass filter of a high frequency amplifier circuit, a standard superheterodyne receiver can be constructed.

In addition, Figure 2 shows an actual photocoupler (Toshiba "TLP").
590A"). In other words, when the load resistance R9H is set to 2.4MΩ, the
It can be seen that when a forward current IF of a+A flows, a boosted voltage of about 6.3V is obtained.

Next, FIG. 3 shows another embodiment of this invention,
It shows the state applied to a digital frequency synthesizer. That is, the boosted voltages output from the photodiode array 19 are respectively supplied to the resonance circuits 2425. Of these, the resonant circuit 25 constitutes a voltage controlled oscillator (VCO) together with the local oscillator 2B, and generates an oscillation output with a frequency corresponding to the boosted voltage applied to the variable capacitance diode D7.

After passing through the voltage buffer circuit 27, this oscillation output is divided by 1/M by a programmable frequency divider 2B that performs a frequency division operation based on an externally set frequency division ratio M, and then sent to one side of the phase comparator 29. is supplied to the input end of

Further, the other input terminal of this phase comparator 29 is supplied with a constant frequency reference signal outputted from an oscillation circuit 30.

The phase comparator 29 compares the frequency and phase of the 1/M frequency-divided signal outputted from the programmable frequency divider 28 and the reference signal outputted from the oscillation circuit 30, and performs control corresponding to the difference component. Generate a signal. This control signal is
The current of the light emitting diode D4 is controlled through an inverting amplifier 31, a loop filter 32 consisting of a resistor R5°R6 and a capacitor C6, and a resistor R7.

That is, in the embodiment shown in FIG. 3, a signal obtained by dividing the oscillation output of a frequency corresponding to the boosted voltage generated from the photodiode array 19 by 1/M and a reference signal are compared in frequency and phase, and the difference component is calculated. The amount of light irradiated by the light emitting diode D4 is controlled so that the light emitted from the light emitting diode D4 is eliminated, and substantially the same effect as the above embodiment can be obtained.

Here, the pressure boosting means using an optical system as in the present invention is
As shown in the above embodiments, this is particularly effective when only the voltage needs to be controlled without flowing current, such as when controlling the bias voltage of a variable capacitance diode.

It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an extremely good booster circuit that does not generate unnecessary radiation, has a simple configuration, and is suitable for downsizing.

[Brief explanation of the drawing]

FIG. 1 is a block circuit configuration diagram showing an embodiment of the booster circuit according to the present invention, FIG. 2 is a characteristic curve diagram showing the characteristics of an actual photocoupler used in the embodiment, and FIG. 3 is a block circuit diagram showing an embodiment of the booster circuit according to the present invention. FIG. 4 is a block circuit diagram showing another embodiment. FIG. 4 is a circuit diagram showing a conventional booster circuit. 11... DC voltage source, 12... Oscillation circuit, 13...
・Step-up transformer, 14... Smoothing circuit, 15... Variable resistor, 16° 17... Resonance circuit, 18... Photocoupler, 19... Photodiode array, 20...
・DC voltage source, 21...gm amplifier, 22...variable resistor, 23...reference voltage source, 24°25...resonance circuit, 2G...local oscillator, 27...voltage bar・Sofa circuit, 28...Programmable frequency divider, 29...
Phase comparator, 30...Oscillation circuit, 31...Inverting amplifier, 32...Lube filter.

Claims (1)

[Claims] A light emitting element driven by a DC voltage source, a photovoltaic element that receives light emitted from the light emitting element and generates a DC voltage at a level corresponding to the amount of light, and a signal and reference corresponding to the output of this photovoltaic element. 1. A booster circuit comprising control means for comparing a signal with a signal and controlling the amount of light emitted from the light emitting element so that the difference component disappears.