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2
votes
2answers
200 views

Feed-forward capacitor in SMPS feedback

I was looking at the TPS63700 DC-DC inverter datasheet and stumbled across the schematic below. It is a more or less usual buck-boost inverter topology schematic, except for the weird R4 and C3 ...
5
votes
2answers
563 views

Controlling MOSFET's resistance using negative feedback

I wanted to use LM317 in a power supply project but wanted to control voltage digitally or with voltage. One possible way was to change one of the voltage divider resistors on the schematic below, ...
0
votes
2answers
523 views

Voltage Feedback Using TL431

Hello All , In the Above circuit , TL431 is used to regulate the output voltage which is set by resistors RH1 and RL1. resistor RB is bias resistor to provide the current to regulate the output ...
1
vote
3answers
101 views

Linear regulator loop dynamics

Given a step change in the input voltage of a standard op-amp based linear regulator, a finite amount of time is needed for the op-amp to sense the voltage difference at its input and do whatever it ...
1
vote
3answers
327 views

TIP127 + TL074 power supply doesn't work until I touch it

I have such a schematic based on the TL074 opamp and the TIP127 PNP darlington transistor to control the fan voltage (shown as motor near the D3 diode). VCC = 12V, VDIG = 5V generated by a LM7805. The ...
2
votes
3answers
568 views

Selecting a capacitor for use in feedback loop

I'm designing a DC Lab Power Supply; the voltage regulation circuit looks like this: I'm developing the BOM, component by component, and next in line is specifying the capacitor in the feedback loop ...
4
votes
2answers
185 views

Why sample current via lopsided resistive divider?

I'm studying the constant-current circuit of the Agilent E3610A 15V 30W DC Bench Power Supply. The entire schematic is at the end of the user manual, but I've redrawn the parts of interest here for ...
2
votes
0answers
638 views

Deriving PI controller transfer function when input is reversed

I'm developing the compensator for the linear DC Bench Power Supply I'm designing. As I've come to deriving the transfer function for the op amp-based compensator, I realize I've been depending on a ...
6
votes
2answers
485 views

What is this RC local feedback configuration?

I'm studying power converter control loops using Christophe Basso's book Designing Control Loops for Linear and Switching Power Supplies. A very common pattern in the compensator circuits is a ...
0
votes
1answer
313 views

Is there a standard symbol for gain margin?

In the context of control loops, specifically power supply control loops in my case, the symbol \$\phi_m\$ is used for phase margin. I've occasionally seen it with a capital M, but on balance it seems ...
1
vote
1answer
84 views

Developing \$C_{out}\$ spec for DC Bench Power Supply

I'm designing a DC Bench Power Supply, following the general design procedure described by Christophe Basso in his book Designing Control Loops for Linear and Switching Power Supplies: A Tutorial ...
6
votes
3answers
612 views

Pass device selection for bench DC power supply

I'm designing a DC Bench Power Supply. This one will be 0-30V, 0-300mA, but I expect I'll try some heftier models once I've gotten this one worked out. I'm following the general design procedure ...
0
votes
1answer
62 views

Can an amplifier charge itself?

My friend asked me this question and I had no answer. Here is what is proposed : An amplifier is fed a current of, say 1 Ampere. Let's say it amplifies it to 100 Amperes. The output is so designed ...
1
vote
1answer
136 views

Feedback in hybrid power supply

During my research of PSU I came across schematic from Linear's datasheet: 1) Whats the purpose of node which is going from output to SW pin of buck converter? 2) Is node which provides 6V headroom ...
0
votes
1answer
193 views

Help understanding onboard power supply measurement test connections

I recently came across this circuit for measuring the output of a TPS54620 switching regulator (12V->3.3V). I'm not a power engineer, so I'd like some help understanding the parts in red boxes (...
3
votes
1answer
657 views

How does feedback in power supply work considering output change delay?

I'm designing an SMPS with a PIC microcontroller, but this question applies not only for SMPS but to linear power supply too. I set a desired output voltage in my microntroller and then I perform ...
0
votes
1answer
4k views

Driving a power transistor with 2sc945

I'm designing a simple 15V to 5V DC voltage feadback mode non SMPS regulator. I'm using E13007E2 power NPN switch mode transistor. And to drive that transistor I'm using C945 another transistor. ...