High Power Amplifier Module

肖某某某

High Power Amplifier Module [Copy link]

 

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I want to make a circuit. Currently, I can only amplify 5V to 20V. But now I want to amplify 0-10V 100KHZ sinusoidal signal to 0-80V. The output current capacity should be 500mA. I can't find such a high-power op amp module. Can you give me some advice? Thank you! Or recommend some amplifiers? Audio amplifiers? Power amplifiers? All are fine.

maychang

How much current can your [0-10V 100KHZ sinusoidal signal] output?

肖某某某

maychang posted on 2024-4-12 16:04 How much current can your [0-10V 100KHZ sinusoidal signal] output?

The output current capacity should not be large. It needs to be amplified to calculate a signal, estimated at mA level.

Is it feasible to use cascade plus push-pull?

maychang

Xiao Moumou published on 2024-4-12 16:31 The output current capacity should not be large. It is to be amplified. It is a signal. Is it feasible to use cascade plus push-pull at the mA level?

The frequency you require is 100kHz, which is much higher than the audio frequency, so all kinds of audio amplifier chips cannot be used directly. The amplitude requires 80V, and ordinary op amps are unable to output voltages with such a large amplitude, so a high-voltage op amp is required. Therefore, a simpler way is to use an NPN Darlington tube and a PNP Darlington tube to form a push-pull amplifier circuit, and use a high-voltage op amp to drive these two tubes. The amplifier circuit constructed in this way has poor efficiency (more amplitude waste), which can barely meet the requirements of your first post.

maychang

Xiao Moumou published on 2024-4-12 16:31 The output current capacity should not be large. It is to be amplified. It is a signal. Is it feasible to use cascade plus push-pull at the mA level?

[Is it feasible to use cascade plus push-pull?]

Does [cascade] refer to [Darlington] connection? If so, that is the appropriate method. Because the output of the op amp is usually limited to 5mA, which is not enough to drive a high-power bipolar transistor.

肖某某某

maychang posted on 2024-4-12 16:50 The frequency you require is 100kHz, which is much higher than the audio frequency, so various audio amplifier chips cannot be used directly. The amplitude requires 80V, and the general op amp...

Yes, I looked around for the audio amplifier but couldn't find it.

肖某某某

maychang posted on 2024-4-12 16:53 [Is it feasible to use cascade plus push-pull?] Does [cascade] refer to [Darlington] connection? If so, it is an appropriate method. Because the output of the op amp is...

Thank you maychang. I have chosen an op amp OPA455. The cascade I mentioned is the op amp cascade. The bandwidth of the op amp is not enough, so two stages are used. However, the output current capacity is not enough, so the current needs to be expanded. But will the current expansion affect the output, such as bandwidth, slew rate, etc.? I don't understand the current expansion.

肖某某某

maychang posted on 2024-4-12 16:50 The frequency you require is 100kHz, which is much higher than the audio frequency, so various audio amplifier chips cannot be used directly. The amplitude requires 80V, and the general op amp...

Does this large amount of waste mean that the op amp power supply is dual power supply, which is more wasteful? Can it be done with a single power supply?

maychang

Xiao Moumou posted on 2024-4-12 17:00 Thank you maychang. At present, I have chosen an op amp OPA455. The cascade I mentioned is the op amp cascade. The bandwidth of the 10x gain op amp is not enough, so two stages are used, ...

How high is the power supply voltage allowed for the op amp OPA455 you selected? An NPN Darlington tube and a PNP Darlington tube form a push-pull amplifier circuit, and the voltage amplification factor is approximately 1, so if the circuit is to output a voltage of 80V, the op amp must also output an amplitude of 80V. In this way, the power supply voltage of the op amp must be greater than 80V.

maychang

Xiao Moumou posted on 2024-4-12 17:01 Does this large amount of waste mean that the op amp power supply is dual power supply, which is more wasteful? Can it be done with a single power supply?

Compared with single power supply and dual power supply, it is more troublesome and the efficiency cannot be improved.

肖某某某

maychang posted on 2024-4-12 17:17 How high is the power supply voltage allowed for the op amp OPA455 you chose? An NPN Darlington tube and a PNP Darlington tube form a push-pull amplifier circuit, and the voltage amplification...

The amplitude is 150V, the bandwidth is 6.5MHZ, and the amplification factor is 1. Do I need to add a voltage follower to the front stage? Can I achieve a 2-fold gain amplification of the front stage?

maychang

Xiao Moumou published on 2024-4-12 17:22 The amplitude is 150V, the bandwidth is 6.5MHZ, and the amplification factor is 1. Do I need to add a voltage follower to the front stage? Can I achieve a 2-fold gain amplification of the front stage?

[Amplitude is 150V, bandwidth is 6.5MHZ, amplification factor is 1]

Your OPA455 has an amplification factor of 1? What signal do you use to drive the OPA455?

肖某某某

maychang posted on 2024-4-12 17:33 [The amplitude is 150V, the bandwidth is 6.5MHZ, and the amplification factor is 1] Your OPA455 amplification factor is 1? What signal do you use to drive the OPA455?

External signal generator 0-10v

肖某某某

maychang posted on 2024-4-12 17:33 [The amplitude is 150V, the bandwidth is 6.5MHZ, and the amplification factor is 1] Your OPA455 amplification factor is 1? What signal do you use to drive the OPA455?

I first use OPA455 to amplify 10 times and then add a voltage follower to the push-pull.

maychang

Xiao Moumou published on 2024-4-12 17:37 I first use OPA455 to amplify 10 times and then add a voltage follower to push-pull like this

[I first use OPA455 to amplify 10 times and then add a voltage follower to push-pull like this]

Oh, the OPA455 amplifies 10 times, so it can't push the bipolar Darlington push-pull?

肖某某某

maychang posted on 2024-4-12 17:54 [I first use OPA455 to amplify 10 times and then add a voltage follower to push-pull like this] Oh, OPA455 amplifies 10 times, and it can't push the bipolar Darlington...

I don't quite understand what "can't push" means. Does it mean that after amplifying ten times, the output current is not large enough?

maychang

Xiao Moumou posted on 2024-4-12 18:53 What does "can't push" mean? I don't quite understand. Does it mean that the output current is not large enough after being amplified ten times?

What does it mean to be unable to push?

[Cannot push] means that the maximum output current of the op amp is less than the base current required by the bipolar power tube. Since the bipolar power tube does not get enough base current, it is of course unable to output the 500mA output current mentioned in the first post.

maychang

Xiao Moumou posted on 2024-4-12 18:53 What does "can't push" mean? I don't quite understand. Does it mean that the output current is not large enough after being amplified ten times?

The current output capability of an op amp with a 10-fold gain is the same as that of a unity gain (1-fold gain, or a voltage follower).

肖某某某

maychang posted on 2024-4-12 18:58 [What does "cannot push" mean?] [Cannot push" means that the maximum output current of the op amp is less than the base current required by the bipolar power tube. Since the bipolar...

I see. So that's how it is.