JPS61280768A - Apd dc high voltage generator circuit - Google Patents

Abstract

PURPOSE:To obtain a DC high voltage of an arbitrary amplitude in a small-sized inexpensive electronic circuit by multiplying to rectify two pulse signals of different phases by a multiplying rectifier having a plurality of diode groups and capacitor groups. CONSTITUTION:A low DC voltage is converted by a pulse signal generator 5 like an astable multivibrator (AMV) into two pulse signals 7, 8 of different phases of 180 deg.. The signals 7, 8 are input to a multiplying rectifier 6 having a plurality of diode groups and capacitor groups, converted to a high DC voltage, and supplied to an avalanche photodiode (APD). Thus, even if a stepup transformer to become a noise generation source is not used, an arbitrary high DC voltage can be produced by a small-sized electronic circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a DC high voltage generation circuit applied to an APD (avalanche photodiode) of an optical receiver used in optical communication.

(Prior Art) The optical receiver of an optical receiver using an APD is equipped with an AP
In order to apply the high DC voltage necessary for the D operation to the APD, two types of DC power supplies, low voltage and high voltage, are required.

An example of a conventional example in which a DC low voltage is used as a power source for a DC high voltage generating circuit of the optical receiver will be described with reference to a block diagram of a conventional optical receiver shown in FIG.

In FIG. 4, for example, 5
DC low voltage such as V, 9V, 12V, etc. is D C-D
It is boosted by the C converter 1 to become a high DC voltage necessary for the operation of the APD 2, and is applied to the cathode side of the APD 2. In the APD 2, the optical input signal is optically amplified and converted into a current signal by the DC high voltage operation, and the load resistor 3 converts the optical input signal into a voltage signal according to the strength of the optical signal. The signal is amplified by the preamplifier 4 which operates as follows.

(Problems to be Solved by the Invention) As a DC power supply for an optical receiver using an APD, two types of DC power supplies, low voltage and high voltage, are provided separately, or a DC- There is a DC high voltage obtained by converting a DC low voltage using a DC converter.

However, the DC-DC converter is composed of an oscillation circuit, a step-up transformer that amplifies the oscillation voltage from the oscillation circuit, and a rectifier circuit, and is structurally large and expensive, and the step-up transformer is There is a problem in that AC high-voltage noise or switching noise very often affects the preamplifier of the optical receiver and becomes interfering noise.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an AMV-based low-voltage DC power supply for the optical receiver without using a step-up transformer.
(astable multivibrator) converts the pulse signal into a pulse signal, and then converts the pulse signal into a multiplier rectifier circuit composed of a diode and a capacitor, and converts it into an arbitrary APD.
The present invention provides a method for converting to DC high voltage for use.

(Function) According to the present invention, the APD high voltage generation circuit having the above configuration is built into the optical receiver, without using a step-up transformer which is a source of interference noise due to AC high voltage.
Any high DC voltage can be generated at low cost using a small electronic circuit.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram of an optical receiver showing a first embodiment of the present invention, and the DC low voltage for operating the optical receiver is TTL
After being converted into two pulse signals with a 180° phase difference by the AMV5, which is simply configured with a (transistor-transistor-logic) IC, the signals are sent to a multiplier rectifier circuit 6 that is configured with multiple diodes and multiple capacitors. It is input and converted to DC high voltage. The optical input signal is optically amplified and converted into a current signal in the APD 2 by the DC high voltage applied to the cathode side of the APD 2, and then converted into a voltage signal according to the strength of the optical signal by the load resistor 3. , is amplified and outputted by the preamplifier 4 operated by the low DC voltage.

FIG. 2 shows the AMV in the first embodiment of the present invention.
5 and a specific circuit diagram of the multiplier rectifier circuit 6 are shown. In FIG. 2, the AMV 5 converts the input DC low voltage into two pulse signals 7 and 8 with a 180° phase difference and supplies them to the multiplier rectifier circuit 6.
The amplitude of 8 can be obtained up to the amplitude of the DC low voltage that drives the TTL of the AMV5, so for example, if the TTL operates with 5V DC, 5■,
A pulse signal with an amplitude of −2 is obtained. Next, as shown in FIG. 2, the multiplier rectifier circuit 6 is composed of a plurality of diodes and a plurality of capacitors, and when the two pulse signals 7.8 are input to the multiplier rectifier circuit 6, Diode 9 conducts only during the positive period of one pulse signal 7,
At the same time, the other pulse signal 8 clamps the negative period via the capacitor 10, so on the cathode side of the diode 9, the amplitude of one of the pulse signals 7 and the amplitude of the other pulse signal 8 are connected via the capacitor 1o. added 2
A pulse signal with twice the amplitude is obtained. Furthermore, the diode 11 is conductive only during the positive period of one pulse signal 8, and at the same time clamps the negative period of the other pulse signal 7 via the capacitor 12. The amplitude of the pulse signal 7 is further added to the amplitude of the pulse signal, which has been doubled, to obtain a pulse signal with a tripled amplitude. As described above, if the diodes and capacitors are connected alternately until the required voltage is obtained, and the other of the capacitors 14 connected to the cathode side of the terminating diode 13 is grounded, the cathode side of the terminating diode 13 is connected to the ground. Any DC high voltage can be obtained. In addition, only the first diode 9 may have its cathode side connected to the low voltage side of DC. According to the hydraulic type, an AMV 5 using a general TTL is operated, and the multiplier rectifier circuit 6 has 5, for example, 6 diodes. By using 1 diode and 6 capacitors, 6 times the DC voltage can be obtained.

For example, a DC high voltage of 30V can be obtained with a DC low voltage of 5V. However, in reality, the multiplied voltage value is somewhat lower than the calculated voltage value due to the forward voltage drop of the diode.

The method of the first embodiment is suitable for obtaining a high DC voltage of several tens of V from a low DC voltage of several V, but requires a huge number of parts in order to obtain a high DC voltage of several hundred V. So,
Economically inefficient. As a second embodiment of the present invention, a DC high voltage generation circuit for efficiently obtaining a DC high voltage of several hundred V from a DC low voltage of several V is constructed as shown in FIG. This will be explained with reference to the block diagram.

In FIG. 3, in the same manner as in the first embodiment of the present invention, the DC voltage output multiplied and rectified by the multiplier rectification circuit 6 is connected to resistors 15, 16 and transistors 17 and 18.
A switching operation is performed via resistors 19 and 20 by two pulse signals 7 and 8 having different phase differences through the AMV5 output 180''.

Two high amplitude pulse signals 21, 22 having a phase difference of 180° are obtained from the collector side of the transistor 17, 18. If the two high-amplitude pulse signals 21 and 22 having a 180° phase difference are input to a second multiplier rectifier circuit 6' having the same configuration as the multiplier rectifier circuit 6, the same operation as that of the multiplier rectifier circuit 6 can be achieved. Accordingly, even higher DC voltage can be obtained. For example, if the first multiplier rectifier circuit 6 and the second multiplier rectifier circuit 6' are each composed of six transistors and six capacitors, and the DC low voltage of AMV5 is 5V, then the first multiplier rectifier circuit 6' 30V by circuit 6
, a DC high voltage of 180V is obtained by the second multiplier rectifier circuit 6'. In addition, the applied voltage of a general APD is as follows.

20-40v for Ge-APD (germanium APD)
The DC voltage of 5i-APD (silicon APD
) requires a high DC voltage of 100 to 250 V.

Further, the current capacity of these APDs is very small, ranging from several nA to several μA.

(Effects of the Invention) As described above, when the current capacity of the APD is very small and a high voltage is required from the DC power supply, the present invention can generate any voltage with an extremely simple circuit configuration, and moreover, Since the amplitude of the signal does not increase, noise generation due to high AC voltage can be reduced, which is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an optical receiver in a first embodiment of the present invention, FIG. 2 is a specific circuit diagram of an embodiment of a DC high voltage generating circuit of the present invention, and FIG. 3 is a block diagram of an optical receiver according to a first embodiment of the present invention. A block diagram of an optical receiver in the second embodiment of the present invention for obtaining a conventional DC high voltage is shown in FIG. 4. 61...D C-DC converter ,
2...API) (avalanche photodiode), 3...load resistor, 4...preamplifier, 5...AMV (astable multivibrator), 6...multiplier rectifier circuit, 6'... Second
Multiplying rectifier circuit, 7.8...Pulse signal, 9,
11.13...Diode, to, 12.14
...Capacitor, 15,16,19゜20...Resistor, 17.18... Transistor, 21゜22...
・High amplitude pulse signal. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2
-0-6Figure 3Figure 4

Claims (2)

[Claims] (1) Two pulse signals taken out with different phases from the pulse signal generation circuit are sequentially multiplied and rectified by a multiplication rectification circuit consisting of multiple diode groups and multiple capacitor groups to obtain a high DC voltage. A characterized by
DC high voltage generation circuit for PD. (2) Two pulse signals taken out with different phases from the pulse signal generation circuit are sequentially multiplied and rectified by a multiplier rectification circuit consisting of a plurality of diode groups and a plurality of capacitor groups. The voltage is further switched by the two pulse signals to create a second pulse signal, and the second pulse signal is sequentially multiplied and rectified by a second multiplier rectifier circuit to obtain an even higher DC high voltage. An APD according to claim (1) characterized in that
DC high voltage generation circuit for use.