KR100277749B1 - Antenna drive device of vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna driving apparatus for a vehicle, and more particularly, to an antenna driving apparatus for a vehicle that allows an antenna pole to be driven electronically through a simple circuit configuration using a transistor.

The present invention includes a first constant voltage conversion unit for stabilizing the battery power to convert the constant voltage for bias; A second constant voltage converting unit which stabilizes a power supply during radio turn-on and converts it into a constant voltage for bias; An overcurrent detector configured to sense an overcurrent generated when the antenna pole is fully lowered or completely lowered; First and second overcurrent controllers that receive a voltage through the overcurrent detector and ground the bias constant voltage generated by the first constant voltage converter; A first switching unit configured to switch battery power to the first relay by an bias voltage generated by the first constant voltage converter and to relay the battery power to an on contact or to an off contact according to the control of the first overcurrent controller; The battery power is switched to the second relay by the bias constant voltages generated by the first constant voltage converter and the second constant voltage converter to be relayed to an on contact or to an off contact according to the control of the second overcurrent controller. Characterized in that it comprises a second switch to make.

Description

Antenna drive device of vehicle

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna driving apparatus for a vehicle, and more particularly, to an antenna driving apparatus for a vehicle that allows an antenna pole to be driven electronically through a simple circuit configuration using a transistor.

1 is a circuit diagram illustrating an antenna driving apparatus of a general vehicle, and the antenna driving apparatus automatically drives the antenna of the vehicle using a clutchless type. In addition, the configuration of the antenna driving apparatus includes an IC chip 11 for controlling the rising or falling of the antenna pole by sensing an input of radio on or off, and a control power applied through the corresponding IC chip. Two NPN transistors Q1 and Q2 for switching power, and two relays RL1 and RL2 for switching to on or off contact depending on the power source switched through the corresponding transistors Q1 and Q2. And a motor 13 for raising or lowering the antenna pole by forward or reverse rotation according to the forward or reverse power applied through the corresponding relays RL1 and RL2, and a plurality of diodes for preventing reverse current of the power supply. D1 to D3, a plurality of capacitors C1 to C8 accumulating the corresponding power supply, and a resistor R1.

As shown in FIG. 2, the IC chip 11 includes a plurality of resistors R1 to R20, two zener diodes ZD1 and ZD2, a plurality of diodes D to D7, and a plurality of resistors. NPN transistors Q3 to Q5, two capacitors C10 to C20, and a plurality of AND gates AND1 to AND4.

Looking at the operation of the antenna driving device made as described above is as follows.

First, referring to the operation of raising the antenna, when the user turns on the radio of the vehicle, the radio on signal is applied to pin 12 of the IC chip 11, the third diode (D3) from the VCC terminal 12) is applied to the 11 pin (Pin) of the IC chip 11 of the battery power (VCC).

Accordingly, the IC chip 11 receives the radio on signal through pin 12 and recognizes the signal as a rising signal of the antenna. The rising signal passes through the second zener diode ZD2 through the 19th resistor R19. It is converted to the rated voltage of 6.8 (V).

Then, the power of 6.8 (V) converted through the second zener diode ZD2 is applied to the base terminal of the fourth transistor Q4 having the emitter terminal grounded through the fifth resistor R5. The fourth transistor Q4 receives a power of 6.8 (V) through the base terminal to perform a switching operation.

Accordingly, since pin 8 connected to the collector terminal of the fourth transistor Q4 is set to a 'low' level, and a 'high' level is applied to the pin 13, the first AND gate AND1 is logically turned on. The power supply is applied to the base terminal of the first transistor Q1 through the seventh resistor R7, and the first transistor Q1 is supplied with the power through the base terminal to perform a switching operation to perform the first relay RL1. Will work.

Then, the motor 12 rotates in the forward direction to raise the antenna pole by consuming an average current of about 0.8 (A) by connecting the VCC terminal and the GND terminal by the ON operation of the first relay RL1.

As the antenna pole is fully raised, an average of about 2.6 (A) of overcurrent is generated, and the voltage rises to a voltage of about 0.7 (V) or more from the first resistor R1 and is applied to the base terminal side of the third transistor Q3. The third transistor Q3 receives the power through the base terminal to perform a switching operation so that the third and gate AND3 are logically turned off.

Then, since the third and gate AND3 is logically turned off to turn on the fifth transistor Q5, the delay time is set by the time constants of the sixth capacitor C6 and the thirteenth resistor R13. The first and gate AND1 are logically turned off so that power is not applied to the base terminal of the first transistor Q1 through the seventh resistor R7, and the first transistor Q1 further performs a switching operation. The motor 12 is no longer rotated because the switch of the first relay RL1 is returned to its original position.

Secondly, when the antenna is lowered, the operation of the radio off signal is no longer applied to the pin 12 when the user turns off the radio of the vehicle, and 0 (V) is also applied to the pin 13. Become the 'low' level.

In addition, since the fourth transistor Q4 does not perform a switching operation, 6.8 (V) is applied to pin 8. That is, the second AND gate AND2 is logically turned on, and power is applied to the base terminal of the second transistor Q2 through the ninth resistor R9.

Accordingly, the second transistor Q2 receives a power through a base terminal to perform a switching operation to operate the second relay RL2, and the motor 12 turns on the corresponding second relay RL2. By connecting the VCC terminal and the GND terminal, the polarity of the antenna pole is reversed when the antenna pole is raised and rotated in the opposite direction to lower the antenna pole.

Then, as the antenna pole is completely lowered, an overcurrent is generated to stop the operation of the motor 12 in the same manner as the stopping operation when the antenna pole is raised.

However, the conventional technology as described above has a very high price using a hybrid IC chip, and the inside of the antenna is very narrow, so it is important to minimize the portion by electronically driving the antenna pole as much as possible. As such, there is a problem that the configuration is very complicated and the problem frequently occurs due to the complexity of the circuit.

In order to solve the problems as described above, the present invention by electronically driving the antenna pole through the configuration of a simple circuit using a transistor, not only to simplify the circuit configuration, but also to reduce the size of the PCB (Printed Circuit Board) and It aims to be able to downsize.

1 is a configuration circuit diagram showing an antenna driving apparatus of a general vehicle.

FIG. 2 is a configuration circuit diagram illustrating an IC chip in FIG. 1. FIG.

3 is a configuration circuit diagram showing an antenna driving apparatus of a vehicle according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

21, 22: constant voltage converter 31, 32: switching unit

41, 42: relay unit 50: motor

60: overcurrent detector 71, 72: overcurrent controller

C1 to C4: Capacitors R1 to R14: Resistance

ZD1, ZD2: Zener Diodes Q1 ~ Q5: Transistor

D1, D2: Diode RL1, RL2: Relay

The present invention for achieving the above object is in the ground state is relayed to the on-contact point to supply the battery power in the reverse direction, and in the ground state is relayed to the on-contact point to supply the battery power in the forward direction An antenna drive device for a vehicle having a second relay unit and a motor for lowering or raising the antenna pole by a reverse or forward battery power applied from the first or second relay unit, wherein the battery power is stabilized. A first constant voltage converting unit converting the constant voltage into a bias constant voltage; A second constant voltage converting unit which stabilizes a power supply during radio turn-on and converts it into a constant voltage for bias; An overcurrent detector configured to sense an overcurrent generated when the antenna pole is fully lowered or completely lowered; First and second overcurrent controllers that receive a voltage through the overcurrent detector and ground the bias constant voltage generated by the first constant voltage converter; A first switching unit configured to switch battery power to the first relay by an bias voltage generated by the first constant voltage converter and to relay the battery power to an on contact or to an off contact according to the control of the first overcurrent controller; The battery power is switched to the second relay by the bias constant voltages generated by the first constant voltage converter and the second constant voltage converter to be relayed to an on contact or to an off contact according to the control of the second overcurrent controller. Characterized in that it comprises a second switch to make.

Hereinafter, with reference to the accompanying drawings will be described as follows.

As shown in FIG. 3, an antenna driving apparatus for a vehicle according to an exemplary embodiment of the present invention includes a constant voltage converter 21, 22, a switching unit 31, 32, a relay unit 41, 42, and a motor. 50, the overcurrent detector 60, and the overcurrent controllers 71 and 72 are included.

The first constant voltage converter 21 stabilizes power B + applied from a battery, and a bias of about 5.6 V that requires the stabilized power for switching control of the first switching unit 31. ) Is converted into a constant voltage and supplied to the first switching unit 31 or the second switching unit 32. In addition, the first constant voltage converter 21 may include a first capacitor C1 for decoupling a high frequency from a power source B + applied from a battery, and a first capacitor C1. A bias of about 5.6 (V) is applied to a stabilized power source through the second capacitor C2 and the first capacitor C1 and the second capacitor C2 that remove low frequency from the high frequency power. Between the first zener diode ZD1 and the second capacitor C2 and the first zener diode ZD1 which are converted into a constant voltage and supplied to the first switching unit 31 or the second switching unit 32. And a first resistor R1 for protecting the first zener diode ZD1.

The second constant voltage converter 22 stabilizes a power applied when the radio is turned on, and the stabilized power is about 5.6 (V) required for switching control of the second switching unit 32. Is converted into a constant voltage for bias and supplied to the second switching unit 32. In addition, the second constant voltage converter 22 may include a third capacitor C3 for removing a high frequency from a power source applied when the user turns on the radio, and a power source from which the high frequency is removed through the third capacitor C3. The second switching unit by converting the power stabilized through the fourth capacitor C4 and the third capacitor C3 and the fourth capacitor C4 to remove the low frequency into a constant voltage for bias of about 5.6 (V). A fifth resistor provided between the second zener diode ZD2 and the fourth capacitor C4 and the second zener diode ZD2 to protect the second zener diode ZD2. (R5) is made.

The first switching unit 31 switches on battery power B + to the first relay unit 41 by performing an on operation by a bias voltage applied from the first constant voltage converter 21. By performing the off operation under the control of the first overcurrent controller 71, the battery power source B + is no longer switched to the first relay unit 41. In addition, the first switching unit 31 receives the bias constant voltage applied from the first constant voltage converter 21 to the base terminal to switch the battery power source B + to the first relay unit 41. The first transistor Q1 and the second and third resistors R2 and R3 for biasing the first transistor Q1 are included.

The second switching unit 32 performs an on operation by the bias constant voltages applied from the first constant voltage converter 21 and the second constant voltage converter 22 to turn on the battery power source B +. The battery unit B + is no longer switched to the second relay unit 42 by switching to the relay unit 42 or performing an off operation under the control of the second overcurrent controller 72. The second switching unit 32 receives the bias constant voltage applied from the second constant voltage converting unit 22 as a base terminal and switches the bias constant voltage applied from the first constant voltage converting unit 21. The main resistor Q3, the sixth and seventh resistors R6 and R7 for biasing the third transistor Q3, and the fourteenth resistor R14 for protecting the third transistor Q3. And a fourth transistor Q4 for switching the battery power source B + to the second relay unit 42 by receiving the bias constant voltage applied by the switching operation of the third transistor Q3 to the base terminal. And the ninth and tenth resistors R9 and R10 for biasing the fourth transistor Q4.

The first relay unit 41 performs a relay operation to the on or off contact by the switching on or off operation of the first switching unit 31 to apply the battery power B + to the motor 50 in the reverse direction. Or the motor 50 is grounded. In addition, the first relay unit 41 is relayed to an on contact by the switching-on operation of the first switching unit 31 to apply a first relay (B +) to the motor 50 in a reverse direction. RL1 and a first diode D1 for bypassing a peak power supply for protecting the first relay RL1.

The second relay part 42 applies a battery power B + to the motor 50 in a forward direction by performing a relay operation to an on or off contact by a switching on or off operation of the second switching unit 32. Or the motor 50 is grounded. In addition, the second relay part 42 is relayed to an on contact by a switching-on operation of the second switching part 32 to apply a second power supply (B +) to the motor 50 in the forward direction. RL2 and a second diode D2 for bypassing a peak power supply for protecting the second relay RL2.

The motor 50 is rotated in the reverse or forward direction by receiving battery power in a reverse direction or a forward direction according to an on contact relay operation of the first relay part 41 or the second relay part 42 to lower or raise the antenna pole. Let it be.

The overcurrent detecting unit 60 has a thirteenth resistor R13 provided between the relay units 41 and 42 and GND, and the motor 50 when the antenna pole is fully raised or lowered. Due to the overcurrent generated by stopping the rotation operation, a voltage of about 0.7 (V) or more is generated in the thirteenth resistor R13 and applied to the overcurrent controllers 71 and 72.

The first overcurrent controller 71 controls the first switching unit 31 to be turned off by performing an on operation by a voltage applied from the overcurrent detecting unit 60. In addition, the first overcurrent controller 71 receives the voltage from the overcurrent detector 60 to the base terminal and performs an on operation to transfer the voltage from the first constant voltage converter 21 to the first switch 31. And a second transistor Q2 for grounding an applied bias voltage, and third and fourth resistors R3 and R4 for biasing the second transistor Q2.

The second overcurrent controller 72 controls the second switching unit 32 to be turned off by performing an on operation by a voltage applied from the overcurrent detecting unit 60. In addition, the second overcurrent controller 72 receives the voltage from the overcurrent detector 60 to the base terminal and performs an on operation to transfer the voltage from the first constant voltage converter 21 to the second switch 32. To protect the fifth transistor Q5 for grounding the applied bias voltage, the eleventh and twelfth resistors R11 and R12 for biasing the fifth transistor Q5, and the fifth transistor Q5. It includes the eighth resistor (R8) for.

An operation of an antenna driving apparatus of a vehicle according to an exemplary embodiment of the present invention will be described as follows.

First, when the antenna pole maintains the falling state, when the user keeps the radio off, the second constant voltage conversion unit 22 is not supplied with power and the first constant voltage conversion unit ( 21) The battery power source B + is applied only to the side.

Accordingly, since the second constant voltage converter 22 does not receive power, the second switching unit 32 and the second relay unit 42, which are components connected to the second constant voltage converter 22, are connected to the second constant voltage converter 22. And the second overcurrent controller 72 does not perform an operation, and the first constant voltage converter 21 receives the power B + from the battery and stabilizes it, and switches the stabilized power of the first switching unit 31. It is converted into a constant voltage for bias of about 5.6 (V) required for control and supplied to the first switching unit 31.

In addition, the first switching unit 31 performs an on operation by the bias voltage applied from the first constant voltage converter 21 to switch the battery power source B + to the first relay unit 41. In addition, the first relay unit 41 performs a relay operation to the on contact by the switching-on operation of the first switching unit 31 to apply the battery power B + to the motor 50 in the reverse direction.

Accordingly, since the plus side of the motor 50 is connected to the first relay portion 41 and the minus side is connected to the second relay portion 42 side, the second relay portion 42 is grounded because it does not perform the operation, and in response to the on-contact relay operation of the first relay unit 41, the battery power in the reverse direction is applied, thereby rotating in the reverse direction to lower the antenna pole.

However, if the antenna pole is in a completely lowered state, the reverse rotation of the motor 50 can no longer be performed, thereby causing an overcurrent. Then, the generated overcurrent is raised to a voltage of about 0.7 (V) or more in the overcurrent detector 60 and applied to the first overcurrent controller 71.

Then, the first overcurrent control unit 71 performs an on operation by the voltage applied from the overcurrent detection unit 60 to control the switching on operation of the first switching unit 31 to be off. The first switching unit 31 does not perform an operation under the control of the first overcurrent controller 71 so that the first relay unit 41 also does not perform an operation.

In other words, the first relay unit 41 grounds the motor 50 by performing a relay operation to an off contact which is in an original state by the switching off operation of the first switching unit 31. The motor 50 no longer performs its operation.

Looking at the lowering operation of the antenna pole as described above in more detail, the first capacitor (C1) to remove the high-frequency components of the power source (B +) applied from the battery, and the first capacitor (C2) Through C1), the low frequency component is removed from the power source from which the high frequency component is removed.

As such, the power stabilized through the first capacitor C1 and the second capacitor C2 is applied from the first zener diode ZD1 through the protective first resistor R1 to bias about 5.6 V. The voltage is converted into a constant voltage and supplied to the first switching unit 31.

Accordingly, the first transistor Q1 of the first switching unit 31 may apply the bias constant voltage applied through the first zener diode ZD1 to the bias second and third resistors R2 and R3. It is applied to the base terminal through the switching on the battery power (B +) to the first relay unit 41.

Accordingly, the first relay RL1 included in the first relay unit 41 is relayed to an on contact by a switching-on operation of the first transistor Q1 to reverse battery power B + to the motor. To 50. In this case, the first diode D1 provided in the first relay unit 41 serves to bypass the peak power of the battery power B + in order to protect the first relay RL1.

Then, the motor 50 receives the reverse battery power in accordance with the on-contact relay operation of the first relay RL1 to rotate in the reverse direction to lower the antenna pole. In this case, the antenna pole is completely lowered. The motor 50 can no longer rotate and generate an overcurrent.

Accordingly, the generated overcurrent causes a voltage to rise at the thirteenth resistor R13 provided in the overcurrent detecting unit 60, and when the corresponding voltage is about 0.7 (V) or more, the first overcurrent controller 71. Will be applied to.

Accordingly, the second transistor Q2 of the first overcurrent controller 71 transfers a voltage from the overcurrent detector 60 to the base terminal through the third and fourth resistors R3 and R4 for bias. The first transistor Q1 is biased from the first constant voltage converter 21 by grounding the bias constant voltage applied by the first constant voltage converter 21 to the first switching unit 31. Since the constant voltage is no longer applied through the base terminal, the switching operation is not performed, and the first relay RL1 also does not perform the operation and is relayed to the original off contact.

Secondly, when the antenna pole rises, when the user turns on the radio, the first constant voltage converter 21 performs the operation as described above to convert the bias voltage into the second switching unit ( 32), and the second constant voltage converter 22 stabilizes the power and converts the stabilized power into a constant voltage for bias of about 5.6 (V) required for switching control of the second switching unit 32. To be supplied to the second switching unit 32.

However, at this time, since the first constant voltage converter 21 supplies a bias constant voltage to the first switching unit 31, the second switching unit 32 is the second constant voltage converter 22 to prevent this. The second relay unit 42 is not supplied to the first switching unit 31 without supplying the bias constant voltage output from the first constant voltage converting unit 21 by the ON operation by the bias constant voltage applied from the first switching unit 31. To be supplied.

Accordingly, the second relay unit 42 performs a relay operation to an on contact by the switching on operation of the second switching unit 32 to apply the battery power B + to the motor 50 in the forward direction. The motor 50 is rotated in the forward direction by receiving the battery power in the forward direction according to the on contact relay operation of the second relay unit 42 to raise the antenna pole.

Accordingly, when the antenna pole is completely raised, the forward rotation of the motor 50 can no longer be performed, resulting in overcurrent. As described above, the generated overcurrent is raised to a voltage of about 0.7 (V) or more in the overcurrent sensing unit 60 and applied to the second overcurrent controller 72.

Then, the second overcurrent controller 72 controls the switching on operation of the second switching unit 32 to be turned off by performing an on operation by a voltage applied from the overcurrent detecting unit 60. The second switching unit 32 does not perform an operation under the control of the second overcurrent controller 72 so that the second relay unit 42 also does not perform an operation.

In other words, the second relay unit 42 grounds the motor 50 by performing a relay operation to the off contact which is in an original state by the switching off operation of the second switching unit 32. The motor 50 no longer performs its operation.

Looking at the rising operation of the antenna pole as described above in more detail, the third capacitor (C3) to remove the high-frequency components of the power source (B +) applied from the battery, and the third capacitor (C4) Through C3), the low frequency component is removed from the power source from which the high frequency component is removed.

As such, the power stabilized through the third capacitor C3 and the fourth capacitor C4 is applied from the second zener diode ZD2 through the fifth resistor R5 to protect the bias of about 5.6 V. The voltage is converted into a constant voltage and supplied to the second switching unit 32.

Accordingly, the third transistor Q3 of the second switching unit 32 receives the bias constant voltage applied through the second zener diode ZD2 to the bias sixth and seventh resistors R6 and R6. Since the switching-on operation is performed by being applied to the base terminal, the bias voltage is prevented from being supplied from the first constant voltage converter 21 to the first switching unit 31 and the corresponding bias voltage is protected. It is applied through the fourteenth resistor R14 to switch to the fourth transistor Q4.

In addition, the fourth transistor Q4 is switched on by receiving a bias constant voltage applied by the switching operation of the third transistor Q3 to the base terminal through the bias ninth and tenth resistors R9 and R10. An operation is performed to switch the battery power source B + to the second relay unit 42.

Accordingly, the second relay RL2 included in the second relay unit 42 is relayed to an on contact by the switching-on operation of the fourth transistor Q4 to turn the battery power B + into the motor in the forward direction. To 50. In this case, the second diode D2 provided in the second relay unit 42 serves to bypass the peak power of the battery power B + in order to protect the second relay RL2.

Then, the motor 50 receives the battery power in the forward direction according to the on-contact relay operation of the second relay RL2 and rotates forward to raise the antenna pole. When the antenna pole is completely raised, The motor 50 can no longer rotate and generate an overcurrent.

Accordingly, the generated overcurrent causes a voltage to rise at the thirteenth resistor R13 provided in the overcurrent detecting unit 60, and when the corresponding voltage is about 0.7 (V) or more, the second overcurrent controller 72. Will be applied to.

Accordingly, the fifth transistor Q5 of the second overcurrent controller 72 transfers a voltage from the overcurrent detector 60 to the base terminal through the eleventh and twelfth resistors R11 and R12 for bias. By applying a switching-on operation to ground the constant voltage for bias applied from the third transistor (Q3) to the fourth transistor (Q4), the fourth transistor (Q4) from the third transistor (Q3) Since the bias voltage is no longer applied through the base terminal, the switching operation is not performed, and the second relay RL2 also does not perform the operation and is relayed to the original off contact.

As described above, according to the present invention, by electronically driving the antenna with a simple circuit configuration using a transistor without using a hybrid IC chip, the size of the PCB can be reduced, the size of the antenna can be reduced, and the overall circuit element is reduced. The cost can be reduced.

Claims (2)

A first relay unit which is in a ground state and relayed to an on contact to supply the battery power in a reverse direction, a second relay unit which is in a ground state and relayed to an on contact and supplying battery power in a forward direction, and a corresponding first or In the antenna driving apparatus of a vehicle provided with a motor for lowering or raising the antenna pole by the reverse or forward battery power applied from the second relay unit, A first constant voltage converter configured to stabilize the battery power and convert the battery power into a constant voltage for bias; A second constant voltage converting unit which stabilizes a power supply during radio turn-on and converts it into a constant voltage for bias; An overcurrent detector configured to sense an overcurrent generated when the antenna pole is fully lowered or completely lowered; First and second overcurrent controllers that receive a voltage through the overcurrent detector and ground the bias constant voltage generated by the first constant voltage converter; A first switching unit configured to switch battery power to the first relay by an bias voltage generated by the first constant voltage converter and to relay the battery power to an on contact or to an off contact according to the control of the first overcurrent controller; The battery power is switched to the second relay by the bias constant voltages generated by the first constant voltage converter and the second constant voltage converter to be relayed to an on contact or to an off contact according to the control of the second overcurrent controller. An antenna driving apparatus of a vehicle, comprising a second switching unit. A first relay unit which is in a ground state and relayed to an on contact to supply the battery power in a reverse direction, a second relay unit which is in a ground state and relayed to an on contact and supplying battery power in a forward direction, and a corresponding first or In the antenna driving apparatus of a vehicle provided with a motor for lowering or raising the antenna pole by the reverse or forward battery power applied from the second relay unit, A first capacitor for removing high frequency from battery power; A third capacitor for removing the high frequency from the power source when the radio is turned on; Second and fourth capacitors which respectively remove low frequencies from the power source that has passed through the first and third capacitors; First and second zener diodes for converting a power supply having passed through the second and fourth capacitors into a constant voltage for bias, respectively; First and fifth resistors for protecting the first and second zener diodes ZD1; A first transistor configured to switch battery power to the first relay unit by a bias voltage passed through the first zener diode; Second and third resistors for biasing the first transistor; A third transistor for switching the bias voltage through the first zener diode by a bias voltage through the second zener diode; Sixth and seventh resistors for biasing the third transistor; A fourteenth resistor for protecting the third transistor; A fourth transistor for switching battery power to the second relay unit by a bias voltage applied through the third transistor; Ninth and tenth resistors for biasing the fourth transistor; A thirteenth resistor that raises the voltage by an overcurrent generated when the antenna pole is fully lowered or completely lowered; A second transistor for grounding a constant voltage for bias applied from the first zener diode to the first transistor by the voltage generated by the thirteenth resistor; Third and fourth resistors for biasing the second transistor; A fifth transistor for grounding the bias voltage applied from the third transistor to the fourth transistor by the voltage generated by the thirteenth resistor; Eleventh and twelfth resistors for biasing the fifth transistor; And an eighth resistor for protecting the fifth transistor.