CN203608159U - Ten-tube large-output-current amplifier circuit structure - Google Patents

Abstract

The utility model discloses a wireless power supply heating lunch box which comprises a box body and a power supply base where the box body can be placed. A heater and an energy receiving coil which are connected are arranged in the bottom of the box body, an energy transmitting coil and an input power source are arranged in the power supply base, and when the box body is placed on the power supply base, the position of the energy receiving coil corresponds to the position of the energy transmitting coil. The wireless power supply heating lunch box has the advantages that power is supplied to the lunch box in an electromagnetic coupling and wireless power supply mode, the 40 W power can be supplied, insufficient energy of battery power supply is improved, and the problem that a plugging lunch box can not be easily cleaned and is unsafe is solved; meanwhile, due to automatic temperature control, multiple heating modes and man-machine interaction interface design of an embedded system, the functions of the lunch box are greatly enriched, and convenience is brought to people. Heat preservation is achieved, the meal quality is guaranteed, and immediate heating can be achieved; meanwhile, due to multiple heating and heat preservation curves, the functions of the lunch box are enriched, and more convenience is brought to living of the people.

Description

The large current amplifiers circuit structure of 10 pipe

Technical field

The utility model relates to a kind of amplifier electric line structure, and more specifically, it relates to the large current amplifiers circuit structure of a kind of 10 pipe.

Background technology

At society, low-noise preamplifier not only applies to daily life field, the equipment such as Source Music, mobile phone, and very extensive in the application in the fields such as transducer, wireless radio transmission, radio communication, thermal imaging, and the signal that receiving terminal receives is conventionally very faint.Preamplifier is positioned at an electronic system of receiver front end, also be applied to detecting small-signal, such as weak signal, the weak signal of antenna reception etc. of various transducer outputs, but existing electronic devices and components generally all exist noise, these small-signals are usually embedded in noise, and various physical quantity (non electrical quantity) is transformed to equivalent voltage signal by transducer and measures.Therefore, require design to aim at the low-noise preamplifier receiving from the small-signal of information source, reduce noise jamming and recall desired signal for For Solutions of Systems.

In order to detect better and transmit small-signal, low-noise preamplifier is absolutely necessary, mostly adopt low noise operational amplifier, but the signal source lower to internal resistance, as heat superconducting galvanic couple thermometric, can not be directly and operational amplifier direct-coupling, need add a matching network, the such circuit structure complexity of optimum Match that just can reach noise, also increases extra noise.In addition, the resistance ratio discrete component of integrated operational amplifier is much bigger, also it was reported that and finds plasma noise, therefore large 2～5 times of the noise ratio discrete component of the similar integrated transporting discharging of circuit structure in integrated circuit.

Summary of the invention

The purpose of this utility model is to overcome deficiency of the prior art, provides a kind of rational in infrastructure, low noise, the large current amplifiers circuit structure of 10 pipe with discrete-semiconductor device composition of high s/n ratio.

The purpose of this utility model is achieved through the following technical solutions.The large current amplifiers circuit structure of this 10 pipe, comprises triode Q1, Q2, Q3, Q4, Q5, Q6, Q7 and Q8, field effect transistor J1 and J2; The grid of J1 meets VS, and the source electrode of J1, J2 connects the collector electrode of the emitter Q3 of Q2, connects the collector electrode of Q5 by electric capacity; The base stage of Q5 connects the emitter of Q4 by diode D2, the emitter of Q5 connects VCC, the collector electrode of Q5 connects D4, the D5 collector electrode to Q6, the emitter that the collector electrode of Q2 connects Q3 by resistance is received VCC, the drain electrode of J1, J2 is connected with the collector electrode of Q1, the base stage of Q1 is passed through grounding through resistance, the emitter of Q1 meets VEE by R4, the grid of J2 connects respectively R16 and R15, R16 ground connection, R15 connects R13 and R14 tie point, and R13, R14 connect Q7 and Q8 emitter, and R13 is with R14 tie point and is connected R17 and RL and arrives; Q8 grounded collector, Q7 base stage connects respectively R11 and R19, and R11 connects Q5 collector electrode, and R19 connects the base stage of Q8; The base stage of Q8 also connects the base stage of R12 to Q6, and the emitter of Q6 connects R10 ground connection.

As preferably: wherein elementary is the FET differential amplifier circuit of J1, J2 composition; Q ₂, Q ₃it is current mirror circuit; Q ₄with Q ₅for Darlington connects; Output stage Q ₇, Q ₈a grade follower OP amplifier is penetrated in the complementation of composition category-B.

The beneficial effects of the utility model are: the bandwidth of the high-power electric current output amplifier of 10 pipe is:

can be obtained by test data analysis such as waveform and amplitude numerical value, system noise is very little, meets low noise requirement.Bandwidth is 1MHz.Signal to noise ratio is: 0.048, realize high s/n ratio.

Accompanying drawing explanation

Fig. 1 is the utility model circuit theory diagrams;

Fig. 2 is test block diagram;

Fig. 3 is test input output waveform.

Embodiment

Below in conjunction with drawings and Examples, the utility model is described further.Although the utility model is described in connection with preferred embodiment, should know, do not represent that the utility model is limited in described embodiment.On the contrary, the utility model is by alternative, modified model and the equivalent contained in the scope of the present utility model that can be included in attached claims restriction.

As shown in Figure 1: a difficult point of this amplifier is to adopt junction type FET.At elementary use FET differential amplifier circuit, the large current amplifiers that the OP amplifier that in the end level is used category-B complementation to penetrate a grade follower [19] forms.

Q2, Q3 are current mirror circuits.Q4 plays a part Darlington with Q5 and is connected.In the time that input is excessive, D3 can prevent that the saturated R9 of the VCE of Q5 from can limit the collector current of Q4.Cf is phase compensation electric capacity.That utilizes that the gm of Cf and elementary J1 can be similar to calculates high frequency open-loop gain:

Output stage Q7, Q8 are category-B work.In category-B work, in each signal half cycle, a side of Q7, Q8 is in cut-off, so as too small in no-load current, signal can not synthesize smoothly, and so-called cross distortion will occur.In addition, the excessive distortion factor that also can make of no-load current degenerates.

Conventionally as set no-load current, making the transmitting voltage across poles of Q7 and Q8 in the time that category-B is worked is 60mV, can control cross distortion minimum.Because the VBE of Q7, Q8 varies with temperature, so must make bias voltage between base stage and base stage also change with identical temperature coefficient, use D6, D7 to compensate bias voltage.Q6 is constant-current circuit.The IC of Q6 is too little, and the equivalent capacity of driver output level completely, if excessive but IC increases, exceedes the PC rated value of Q5 and Q6, and reliability will decline.The electrical power by-pass electric capacity that the amplifier of large output current is provided, its capacitance must increase with output current.

As shown in Figure 3, it is 100mVPP that input is accessed to amplitude, and frequency is 1KHz sine wave, and access oscilloscope is observed waveform, and A channel connects output, and B passage connects input.Known according to the observation, circuit multiplication factor is about 20 times.

In the situation that operating voltage is positive and negative 12V, first access 100mV, the sine wave signal that frequency is 1KHz, as source signal, with oscilloscope measurement input and output end signal, is observed its V _iwith Vo, according to formula:

The large current amplifiers voltage record of 10 pipe

?	Signal source Vs (1KHz)	Input Vi (1KHz)	Output end vo (1KHz)
				Vmax	55mV	52.8mV	1.10V
Vmin	-55mV	--54.4mV	-1.08V
				Vpp	100mV	107mV	2.18V

$K_u=\frac{V_S}{V_O}=\frac{2.18V}{107\mathrm{mV}}\≈20.37$

So the actual measurement multiplication factor of circuit is about 20.37 times, the power of circuit is 14.652mW.

At input incoming transport small-signal, output termination voltmeter, changes the frequency of input signal, when turning frequency down, makes multiplication factor become 1/2 o'clock of former multiplication factor, is f _l, in like manner, heighten frequency, make multiplication factor become 1/2 o'clock of former multiplication factor, be f _h.

The large current amplifiers bandwidth measurement of 10 pipe

K U	f L	f H	B
				20.37	<1Hz	1MHz	1MHz

In a signal source of input access, make its amplitude constant, change its frequency, observe phase place variation record do not occur

The large current amplifiers linearity measure of 10 pipe

K U	f L’	f H’
			20.37	<1Hz	3MHz

By input short circuit, measure the noise voltage of output: Uon=42.606mV

$e_n=U_{\mathrm{on}}/K_u\sqrt{B_{\mathrm{eq}}}=2.09\×{10}^{-6}V/\sqrt{\mathrm{Hz}}$

Input impedance, as shown in Figure 2, accesses resistance and the 1V power supply of 51 Ω at the input of circuit board, measure respectively A point and B point voltage, can obtain: Z according to the computational methods similar to last chapter _in=47K

Output impedance, sensing lead both end voltage, measures output end voltage after dismounting load, can be calculated: Z _l=290 Ω

The large current amplifiers voltage range of 10 pipe

?	Input voltage	Output voltage
			Maximum non-aliased voltage	282mV	16.635V
Minimum undistorted voltage	10mV	830mV

Claims (2)

1. the large current amplifiers circuit structure of 10 pipe, is characterized in that: comprise triode Q1, Q2, Q3, Q4, Q5, Q6, Q7 and Q8, field effect transistor J1 and J2; The grid of J1 meets VS, and the source electrode of J1, J2 connects the collector electrode of the emitter Q3 of Q2, connects the collector electrode of Q5 by electric capacity; The base stage of Q5 connects the emitter of Q4 by diode D2, the emitter of Q5 connects VCC, the collector electrode of Q5 connects D4, the D5 collector electrode to Q6, the emitter that the collector electrode of Q2 connects Q3 by resistance is received VCC, the drain electrode of J1, J2 is connected with the collector electrode of Q1, the base stage of Q1 is passed through grounding through resistance, the emitter of Q1 meets VEE by R4, the grid of J2 connects respectively R16 and R15, R16 ground connection, R15 connects R13 and R14 tie point, and R13, R14 connect Q7 and Q8 emitter, and R13 is with R14 tie point and is connected R17 and RL and arrives; Q8 grounded collector, Q7 base stage connects respectively R11 and R19, and R11 connects Q5 collector electrode, and R19 connects the base stage of Q8; The base stage of Q8 also connects the base stage of R12 to Q6, and the emitter of Q6 connects R10 ground connection.

2. the large current amplifiers circuit structure of 10 pipe according to claim 1, is characterized in that: the wherein elementary FET differential amplifier circuit for J1, J2 composition; Q ₂, Q ₃it is current mirror circuit; Q ₄with Q ₅for Darlington connects; Output stage Q ₇, Q ₈a grade follower OP amplifier is penetrated in the complementation of composition category-B.

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