Power Electronics (Page 2)

Power Controls, Supplies, Drives.

PowerEsim – Online power supply design

PowerESIM is a eCAD tool for switching power supplies on the Internet. Web Based Switching Power Supply design and Simulation.

PowerEsim – Online power supply design

The most important characteristic powerEsim is that it provide a virtual laboratory environment for engineer to verify and fine tune their design. Experience engineer use it to optimize their design by saving a lot of time than in real bench.

The circuit simulator is a combination of iteration, equation based apporoach and time step integration. The circuit is defined by non-linear equations and the simulator will first solving the switching condition solution for t=infinity by bracketed iteration, then fine step of point by point results will be generated by those equations for V, I and loss analysis.

“In a real laboratory, engineers have the ability to feel the heat, measure the stress, wind real transformers and wait and see how long until the unit gets burned. With our seamless integration of a variety of tools such as thermal, MTBF, Life, DVT, Waveform, etc., users can now do the same things in PowerEsim virtual environment.”

Simple WorkBench Dual Power Supply

I will just explain part of this circuit. D9 and D10 provide a low cost -1.4 from -5 V. This is needed to reach near 0.00 for LM317 Min. setting. An LED also can be used with proper bias. Note that there is a Temperature Coefficient in ppm,  but it may not matter upto 8 bits accuracy.

TIP2955, TIP3055 (NPN), TIP2955 (PNP) Complementary Silicon Power Transistors. It is a Darlington, that means good current gain. When current in R1 10E goes more than 50mA a voltage of 50mA X 10E = 500mV is applied across Emmiter-Base junction. So lower than 500mV no bias the tap is turned off, 500mV-700mV the tap starts turning on depending on type of transistor.

Power Supplies Section

The transistor is like a water Tap. So TIP2955 carries the major current burden thru the load allowing LM317 to do the decision making when to turn-on or off. It is analog control, it is not On-Off but linear-proportional. The LM317 is very cool as the burden is passed off to TIP2955 who will need a heatsink to keep going and deliver the power you want.

Put the filter caps appropriately. The Hum-Noise will be filtered. The cap after the regulator should be a small guy. The main filter cap after the Bridge can be as big as your cabinet or budget.

Mains Voltage Power Transformers

If you build it and wire it without designing a PCB, then make all wiring and connection very sound. The test of this ability you can know easily, If your project stops working after the last screw of the cabinet is tightened, Then we need to improve.

PWM Control Circuit – TL494

The TL494 incorporates all the functions required in the construction of a pulse-width-modulation (PWM) control circuit on a single chip. Designed primarily for power-supply control, this device offers the flexibility to tailor the power-supply control circuitry to a specific application.

PWM Control Circuit – TL494

• Complete PWM Power-Control Circuitry
• Uncommitted Outputs for 200-mA Sink or Source Current
• Output Control Selects Single-Ended or Push-Pull Operation
• Internal Circuitry Prohibits Double Pulse at Either Output
• Variable Dead Time Provides Control Over Total Range
• Internal Regulator Provides a Stable 5-V Reference Supply With 5% Tolerance
• Circuit Architecture Allows Easy Synchronization

The TL494 contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, a 5-V, 5%-precision regulator, and output-control circuits.

SG2525 – SG3525 – PWM SMPS Regulator Chip

SG2525 – SG3525 – PWM SMPS Regulator Chip. A second generation ic switch mode controller optimized for high frequency.

100kHz Half Bridge Convertor – SG3525

The SG3525A pulse width modulator control circuit offers improved performance and lower external parts count when implemented for controlling all types of switching power supplies. The on-chip +5.1 V reference is trimmed to +/-1% and the error amplifier has an input common-mode voltage range that includes the reference voltage, thus eliminating the need for external divider resistors. Half Bridge, Push-Pull.

SG3525 usage in SMPS 500W – It was used in Parallel for Electroplating with a central Load sharing control between modules.

Specs

• 8.0 V to 35 V Operation
• 5.1 V +/- 1.0% Trimmed Reference
• 100 Hz to 400 kHz Oscillator Range
• Separate Oscillator Sync Pin