CN104539150A

CN104539150A - Drain electrode modulator circuit with slow start function

Info

Publication number: CN104539150A
Application number: CN201410815763.1A
Authority: CN
Inventors: 李兵; 张娟; 雷国忠; 吕元恒; 李磊; 白树林
Original assignee: Xian Electronic Engineering Research Institute
Current assignee: Xian Electronic Engineering Research Institute
Priority date: 2014-12-23
Filing date: 2014-12-23
Publication date: 2015-04-22

Abstract

The invention relates to a drain electrode modulator circuit with a slow start function. The drain electrode modulator circuit comprises a transistor, a P-channel MOS transistor, a divider resistor and an N-channel field-effect transistor self-biased slow start function circuit. According to the technology, the principle that the channel impedance of an N-channel field-effect transistor is gradually increased along with the decreasing of the voltage difference of a gate source is used, a capacitor is slowly charged, and when the charging voltage reaches a set threshold, a time-sharing modulation circuit is used for conducting boost charge.

Description

A kind of drain modulation circuit with slow turn-on function

Technical field

The present invention relates to Radar Technology field, the power supply modulator circuit specifically in complete solid state pulse radar transmitter time sharing power supply.

Background technology

Needed for transmitter, DC power supply contains ripple voltage, this ripple voltage may to amplifying signal produce modulation, for class A amplifier, due to gate bias change time, the angle of flow is constant, does not produce modulating action; Then there is modulation in various degree for class AB or class B amplifier, this modulation can occur in receivers with the form of clutter, and therefore power supply is the most important factor causing transmitter to export clutter.Although lower noise level can be obtained by reducing power supply ripple, a lot of cost and difficult design can be increased for power supply.In order to reduce the impact of Power supply ripple on transmitter, improve radar moving targets improvement factor, general employing is charged to storage capacitor by power supply at inter-train pause, and do not work at impulse duration power supply, there is provided required pulse current by storage capacitor for all amplifiers, doing so avoids the ripple of Switching Power Supply and the interference of high frequency sparkle noise radio frequency signal.But the problem that this supply power mode is brought is power supply when carrying out primary charging to electric capacity, immediate current can reach thousand A levels, the field effect transistor overcurrent in drain modulation circuit is caused to burn, so, design a novel drain electrode modulation circuit with the slow output function of voltage and just seem necessary.

Summary of the invention

The technical problem solved

In order to solve in complete solid state pulse radar transmitter time sharing power supply, when power supply carries out primary charging to electric capacity, in the excessive traditional drains modulation circuit caused of immediate current, the overcurrent of field effect transistor burns, and then causes the inefficacy of drain modulation circuit.The present invention proposes a kind of drain modulation circuit with slow turn-on function.

Technical scheme

There is a drain modulation circuit for slow turn-on function, comprise transistor, P channel MOS tube, divider resistance; Characterized by further comprising N channel field-effect pipe automatic biasing slow turn-on functional circuit; Described N channel field-effect pipe automatic biasing slow turn-on functional circuit comprises N-channel MOS pipe and four divider resistances and multiple diode, first divider resistance R4 connects the drain and gate of N-channel MOS pipe, after second divider resistance R5 and multiple Diode series between the grid and source electrode of N-channel MOS pipe, 3rd divider resistance R6, the 4th divider resistance R7 N-channel MOS pipe source electrode and ground between, the drain electrode of described N-channel MOS pipe is connected with the source electrode of P channel MOS tube, and the source electrode of N-channel MOS pipe is connected with the drain electrode of P channel MOS tube.

The voltage difference at the first described divider resistance two ends is greater than the grid source pinch-off voltage of N-channel MOS pipe.

Described diode is 4.

Beneficial effect

A kind of drain modulation circuit with slow turn-on function that the present invention proposes, guaranteeing in the impregnable situation of original power modulation performance, when power supply carries out initial charge to electric capacity, utilize the principle that N channel field-effect pipe channel impedance increases gradually with the reduction of grid source pressure reduction, realize slowly charging to electric capacity, make the transient current that electric power starting moment unlikely generation is very large, avoid the damage of metal-oxide-semiconductor and the inefficacy of drain modulation circuit.

Accompanying drawing explanation

There are in Fig. 1 the present invention the drain modulation circuit theory diagrams of slow turn-on function

There is in Fig. 2 the present invention the drain modulation circuit measured drawing of slow turn-on function

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

In radar transmitter, adopt the object of time division modulation circuit to be quit work to make power amplifying device turn off gap at radio-frequency pulse, power supply charges to storage capacitor, during transmitted pulse, power supply does not work, and powers to power amplifier by storage capacitor.Time division modulation circuit is made up of amplifier two parts modulation circuit of powering capacitor charging and impulse duration electric capacity inter-train pause power supply, electric capacity is powered to amplifier and traditional drain modulation circuit can be taked to realize, and the problem that power supply adopts the metal-oxide-semiconductor that transient high-current can be brought to cause during traditional drain modulation circuit to damage to capacitor charging.In the present invention, the scheme that we take is: electric power starting moment, slowly charged to electric capacity by slow start circuit, when charging voltage reaches the threshold level of our setting, open exomonental back pulse, carry out boost charge, until supply voltage by traditional drain modulation circuit; In transmitter normal work period, because the pressure drop of storage capacitor is very little, capacitance voltage is higher than the threshold level arranged in our slow start circuit, slow start circuit will no longer work, modulation function has been come by traditional drain modulation circuit, thus ensure that power source charges speed, electric capacity can be full of in inter-train pause.

Slow start circuit is made up of a N-channel MOS pipe and four divider resistances and several diode.In practical work process, owing to there being the existence of N-channel MOS pipe, power supply can not directly charge to electric capacity, but is slowly charged to electric capacity by N-channel MOS pipe.First supply voltage adds to the drain electrode of N-channel MOS pipe, its source voltage is 0V, grid voltage is the dividing potential drop of divider resistance and diode pair supply voltage, by adjusting the resistance of divider resistance, make the difference of gate source voltage be greater than the cut-ff voltage of N-channel MOS pipe, make its conducting and export drain voltage to source electrode.Along with charging continue carry out, source voltage progressively raises, and grid voltage declines gradually, and the pressure reduction between grid source is less gradually, and the channel impedance of N-channel MOS pipe increases gradually, and charging rate also can be slack-off.By divider resistance, dividing potential drop is carried out to charging voltage, it is detected, and send into the control program of transmitter and threshold level that we set compares by detecting level, when charging voltage reaches threshold level, open exomonental back pulse, boost charge is carried out, until supply voltage by traditional drain modulation circuit.

As Fig. 1, when power supply carries out primary charging to electric capacity C1, the voltage of electric capacity C1 is 0V.First do not open exomonental back pulse Pulse_in, the pulse control signal of input is low level, transistor MMBT5551 not conducting, resistance R2, R3 cannot carry out dividing potential drop to Vin, without enough conducting cut-in voltages between P channel MOS tube IRF5210 grid-source electrode, device turns off, therefore can not be charged to electric capacity by the drain modulation circuit of the latter half.The circuit of the first half dotted line frame inside is the N channel field-effect pipe automatic biasing slow turn-on functional circuit proposed in the present invention, when power supply initial power-up, the source voltage of N-channel MOS pipe FDB3632 is 0V, grid voltage is that resistance R4, R5 and four diode 1N4007 are to the dividing potential drop of supply voltage Vin, by choosing suitable R4, R5 resistance value, make the voltage difference at R4 two ends be greater than the grid source pinch-off voltage of N-channel MOS pipe, can make FDB3632 conducting, power supply starts to charge to electric capacity; Along with charging continue carry out, source voltage progressively raises, and grid voltage declines gradually, and the pressure reduction between grid source is less gradually, and the channel impedance of FDB3632 increases gradually, and charging rate also can be slack-off.In Fig. 1, resistance R6, R7 carry out dividing potential drop to charging voltage, are detected level and are set to DET, and send into the control program of transmitter, in implementation process, this level are set to 46V.

When output voltage reaches the threshold level of setting, the control program of transmitter sends instruction, opens exomonental back pulse Pulse_in, and namely in transmitted pulse gap, the latter half time division modulation circuit in Fig. 1 carries out boost charge to electric capacity.When input pulse control signal is low level, transistor MMBT5551 not conducting, resistance R2, R3 cannot carry out dividing potential drop to Vin, without enough conducting cut-in voltages between P channel MOS tube IRF5210 grid-source electrode, device turns off, and now Vout keeps the voltage output value 46V of slow start circuit; When input pulse control signal is high level, transistor MMBT5551 conducting, resistance R2, R3 carry out dividing potential drop to Vin, voltage difference between P channel MOS tube IRF5210 grid-source electrode is the voltage difference at resistance R3 two ends, as long as this voltage difference is greater than the grid source cut-in voltage of IRF5210, be less than the voltage limit parameter between grid source, the conducting of IRF5210 raceway groove can be made, by power supply Vin, boost charge is carried out to electric capacity, until supply voltage 52V.In Fig. 1, the Main Function of transistor DB139 and diode ES2B promotes rising edge, trailing edge response speed, improves the switching speed of modulation circuit.In implementation process, circuit each component parameter value is as shown in table 1, and measured result as shown in Figure 2.

Table 1 circuit components parameter

R1

R2

R3

R4

R5

R6

R7

C1

Vin

560

2.2k

1.1k

1k

390

10k

560

30000u

52V

Claims

1. there is a drain modulation circuit for slow turn-on function, comprise transistor, P channel MOS tube, divider resistance; Characterized by further comprising N channel field-effect pipe automatic biasing slow turn-on functional circuit; Described N channel field-effect pipe automatic biasing slow turn-on functional circuit comprises N-channel MOS pipe and four divider resistances and multiple diode, first divider resistance R4 connects the drain and gate of N-channel MOS pipe, after second divider resistance R5 and multiple Diode series between the grid and source electrode of N-channel MOS pipe, 3rd divider resistance R6, the 4th divider resistance R7 N-channel MOS pipe source electrode and ground between, the drain electrode of described N-channel MOS pipe is connected with the source electrode of P channel MOS tube, and the source electrode of N-channel MOS pipe is connected with the drain electrode of P channel MOS tube.

2. the drain modulation circuit with slow turn-on function according to claim 1, is characterized in that the voltage difference at the first described divider resistance two ends is greater than the grid source pinch-off voltage of N-channel MOS pipe.

3. the drain modulation circuit with slow turn-on function according to claim 1, is characterized in that described diode is 4.