JPH01321725A - Switch driver - Google Patents

Abstract

PURPOSE:To switch a drive voltage to negative and positive with a control signal having a single polarity by connecting an input terminal to a first control terminal and a second resistance through a first resistance and connecting the input terminal to a Zener diode and a second control terminal through a third resistance. CONSTITUTION:A diode switch circuit 21 consists of capacitors C1 and C2, choke coils L1 and L2, and a diode D1. When the voltage between terminals 16 and 17 is positive, the circuit is driven to be turned on because the diode D1 is forward biased. When the voltage between terminals 16 and 17 is negative, the circuit is turned off because the diode D1 is backward biased. Thus, the drive voltage applied to the first and second control terminals of a semiconductor switching element is switched to positive and negative by the control signal having a single polarity.

Description

[Detailed Description of the Invention] [Summary] Regarding a switch driver that controls switching by driving a semiconductor switching element such as a diode, positive/negative switching of the drive voltage is performed using ψ-polarity &IJtll.
Intended to be done with signals,! ! II signal input terminal and the first semiconductor switching element
a first resistor connected between the first resistor and the first control terminal, and a second resistor connected between the connection point of the first resistor and the first control terminal and ground; and a control rlJ signal input terminal. and a third resistor connected between the second &IJtXI terminal of the semiconductor switching element, and a Zener diode connected between the connection point of the second i/Itll terminal and the third resistor and ground. , the semiconductor switching element is driven by changing the first and second control voltages of the semiconductor switching element using a single-polarity control signal input to the input terminal.

[Industrial application field]

The present invention relates to a switch driver, and particularly to a switch driver that controls switching by driving a semiconductor switching element such as a diode.

Diodes are used as semiconductor switching elements in various circuits. For example, it is also used in microwave band phase shifters as shown in FIGS. 5(A) and 5(B). Figure 5 (A) shows the microstrip line 1 connected to the diode 2.
is connected to one end of a straight microstrip line 3 through a diode 4, and connected to one end of a U-shaped microstrip line 5 through a diode 4, and the other end of the microstrip line 3.5 is connected to a diode 6. 7 shows a phase shifter configured to be commonly connected to a microstrip line 8 through a microstrip line 8, which is called a loaded phase shifter.

In this loaded phase shifter, the microstrip line 3
．． 5, different delay times can be obtained, and the input microwave signals are alternately supplied to the microstrip lines 3 and 5, and the microwave signals propagated through the microstrip lines 3 and 5 are alternately supplied. is supplied to the microstrip line 8.

Moreover, FIG. 5(B) uses a low-pass filter 9 and a bypass filter 10 instead of the microstrip lines 3 and 5, and is called a bypass low-pass type phase shifter. This bypass low-pass type phase shifter is configured to obtain different delay times from the bypass filter 9 and the low-pass filter 10, and is similar to the loaded phase shifter in that microwave signals are alternately supplied to these filters.

In each of the above phase shifters, diodes 2, 4, 6 and 7 are used for switching; when diodes 2, 6 are on, diode 4, 7 is off, and diodes 2, 4, 6 and 7 are off.
When 6 is off, diode 4.7 is on.

A switch driver is required to control the switching of switching diodes used in such phase shifters and other devices.

[Conventional technology]

FIG. 6(A) shows a circuit diagram of an example of a conventional switch driver. In the figure, the input terminal 11 is connected to a common connection point between the 7 nodes of the diode Do and the capacitor +lCa via a resistor Ra and a choke coil La in series. Also,
Input terminal 12 is connected to a common connection point between the cathode of diode Do and capacitor cb via choke coil Lb. A fixed reference voltage is input to the input terminal 12, and switching i, 1Jtil signals are input to the input terminal 11. This control signal has a pulse waveform as shown in FIG. 6(B), and during the period when the level is higher than the reference voltage, the diode Do is forward biased and turned on. On the other hand, during the period when the level is lower than the reference voltage, the diode Do is turned on. Diode Do is reverse biased to turn it off.

While the diode Do is on, the input signal input via the capacitor Ca passes through the diode Do and is further output via the capacitor cb.

On the other hand, while the diode Do is off, the human input signal input to the diode Do via the capacitor Ca is blocked from passing through the diode Do.

In this way, in this conventional switch driver, the control signal has the same polarity as the reference signal and always has either positive or negative polarity (i.e., single polarity), and the control signal is at a higher level than the reference voltage. Diode switching is controlled by low level.

In addition, as another conventional switch driver, Fig. 7 (A>
A configuration as shown in is known.

In FIG. 6A, the same components as those in FIG. In this conventional switch driver, the negative end of the choke coil Lb is grounded, no reference voltage is input, and the control signal input terminal 13
It is characterized in that control signals of both positive and negative polarities are input as shown in FIG. 7(B).

That is, when the &IJtll signal has positive polarity, diode Do is turned on, and when it has negative polarity, diode Do is turned off.

[Problem to be solved by the invention]

However, the conventional switch driver shown in FIG. 6(A) requires two lines, t and IJ, a large input line and a reference voltage input line, for switching the diode Do.
In addition, a separate reference voltage generation source was required.

Furthermore, the conventional switch driver shown in Fig. 7 (A) does not require a reference voltage source, but on the other hand, as shown in Fig. 7 (B), the positive polarity is Since both negative polarities are required, the circuit for generating this control signal is somewhat complicated, and if the system power supply has a single polarity, it is not possible to output the control signal itself.

The present invention has been made in view of the above points, and an object of the present invention is to provide a switch driver that can change the positive and negative 17JFIA of the drive voltage using a single-pole control signal.

[Means for solving the vR problem]

FIG. 1 shows an original circuit diagram of the present invention. 15 is a control signal input terminal, 16 and 17 are the first semiconductor switching elements.
and a second control terminal. R+, R2 and R3 are respectively 1. The second and third resistors, Dz, are Zener diodes.

The input terminal 15 is connected to a first control terminal 16 and a second resistor R2, respectively, via a first resistor R1, and to a Zener diode Dz and a second control terminal 17, respectively, via a third resistor R3. It is connected.

A single polarity control signal is input to the input terminal 15, and the first
and the second control terminal 16,17 is varied, thereby driving the semiconductor switching control element.

[Effect]

The voltage value of the control signal of the input terminal 15 is Vc, the Zener voltage of the Zener diode Dz is Vz, and the control terminal 16.17
Assuming that the voltage between them is Vo, and the resistance values of the resistors R1 to 3 are also written as <R+ to R3, the following equation holds true depending on the magnitude relationship between the voltage Vc and the Zener voltage Vz.

■If Vc > Vz, Vo = (R2/ (R1+Rz)) ・Vc
-Vz here, tIII sin signal Vc is divided by resistance, T
(9Tffi'l wJJ The voltage VA at the child 16 is (R2/(R2R2))・Vc, which is the control I
It is selected to be larger than the voltage Ve at the terminal 17 (ie, the Zener voltage Vz). Therefore, the voltage Vo at this time becomes positive.

(2) When Vc<Vz In this case, the voltage V[J at the control terminal 17 becomes Vc since the control signal Vc is smaller than the Zener voltage Vz. Therefore, VD=((R2/(R1+R2))-1)·Vc■. In Equation 0, R2/(R1+R2) is smaller than 1, so VD of Equation 0 is negative.

Here, as an example, let R+ = Rz = R3 - 5000°Vz = 6V, and the voltages V^, Va and Vc will be as shown in Fig. 2 (A>). Therefore, the voltage Vo (=V^
-Ve ) becomes negative when VA<Va, as shown in FIG. 2(B), and VA-Ve -6V (at this time Vc-
It becomes positive at a voltage of 12V) or higher.

In this way, although the value Vc of the iqmt signal has a single polarity (here, positive polarity), by changing the value Vc, the first and second control terminals 16, 17 of the semiconductor switching element The voltage Vo between them can be changed between positive and negative polarities.

Therefore, when a diode is used as a semiconductor switching element as shown at 18 in FIG. 1, its forward current 1d flows as shown in FIG. Since no current flows, switching of the diode 18 can be controlled.

Note that the forward current 1d is determined by the resistor R1, and is Vc
A reverse voltage of 3V is applied to the bridging diode 18 whose voltage is 6V, and when Vc is 18V, a forward current of 6mA flows.

〔Example〕

FIG. 3 shows a circuit diagram of a first embodiment of the invention.

In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. In FIG. 3, 20 is a switch driver of the present invention, and 21 is a diode switch circuit. The diode switch circuit 21 has a capacitor C+, 0
2 *Choke coil L+, 12 and diode D+
It becomes more.

As mentioned above, depending on the value Vc of the control signal, the terminal 16.
17 is controlled to be positive or negative.

Here, when the voltage between the terminals 16 and 17 is positive, the diode D1 is biased in the forward direction and is therefore driven to be turned on. On the other hand, when the voltage between terminals 16 and 17 is negative, diode D+ is biased in the reverse direction, so
It turns off.

FIG. 4 shows a circuit diagram of a second embodiment of the invention.

In the figure, the same components as in FIGS. 1 and 3 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 4, 22 is a field effect transistor (FET) switch circuit, which includes a semiconductor switching element FETQ+, capacitors C3 and C4 connected to its drain and source, respectively.
A coil L3.Q1 connected between the gate and source of Ql and terminal 16.17. It consists of L4. Assuming that Ql is an N-channel FET, when the voltage Vo is changed positively by the control signal Vc to drive the FET switch circuit 22, Ql is turned on. Further, the voltage V
When o is changed to a negative value to drive the FET switch circuit 22, Ql is turned off.

As described above, regardless of whether the voltage Vo is set to either positive or negative polarity, the value Vc of the control l signal is always positive, for example, and the only difference is the level. Therefore, switching of FET Ql can be controlled by a single-pole control signal Vc.

〔Effect of the invention〕

As described above, according to the present invention, the drive voltage applied to the first and second control terminals of the semiconductor switching element can be switched between positive and negative by a single polarity control signal,
Therefore, it can be applied to systems that only have a single-polarity power supply, and it also has features such as no need to provide a reference voltage source and can be constructed at a lower cost than conventional circuits that require a reference voltage source. It has the following.

[Brief explanation of the drawing]

Fig. 1 is the original circuit diagram of the present invention, Fig. 2 is a voltage and current characteristic diagram of each part of Fig. 1, Fig. 3 is a circuit diagram of the first embodiment of the present invention, and Fig. 4 is the circuit diagram of the present invention. The circuit diagram of the second embodiment, FIG. 5 is a diagram showing each phase shifter, and FIGS. 6 and 7 are diagrams showing a conventional circuit diagram and waveform diagram, respectively. In the figure, 15 is the 1III1D signal input terminal, 16 is the first 1110 terminal, 17 is the second υ+m terminal, 18, D+ is the diode, R1 is the first resistor, R2 is the second resistor, R3 is the third resistor , Dz is a Zener diode, and Ql is a field effect transistor (FET). 111 Figure 1, 2, 9, 1, 2, 1, 2, 4, 3, 1, f) 8# voltage, electric skin recess, Figure 2, 114 @ 5, Figure 6! ! I 7th! ! I

Claims (1)

[Claims] A first resistor (R_1) connected between a control signal input terminal (15) and a first control terminal (16) of a semiconductor switching element; and the first resistor (R_1). and the first control terminal (16
) and the second resistor (R_2) connected between the connection point of
and a third resistor (R_3) connected between the control signal input terminal (15) and the second control terminal (17) of the semiconductor switching element; It consists of a Zener diode (Dz) connected between the connection point of the resistor (R_3) and the ground, and the first and second semiconductor switching elements are controlled by a single polarity control signal input to the input terminal (15). A switch driver characterized in that the semiconductor switching element is driven by changing the voltage between the control terminals (16, 17) of the switch driver.