SG3525 | Electronic Project Circuits

Posts Tagged ‘SG3525’

SG3525 DC Converter 12V to +35V,-35V

SG3525 DC/DC Converter 12V to +35V,-35V Switchmode Power Supply For Car Audio

The selected switching topology is called a “push-pull” converter, because the transformer has a double primary (or a “centre-tapped” one, if your prefer). The centre tap is permanently connected to the car battery (via an LC filter to avoid creating peaks in the battery lines, which could affect other electronic equipment in the car). The two ends of the primary are connected to a pair of paralleled MOSFETs each that tie them to ground in each conduction cycle (Vgs of the corresponding MOSFET high).

These MOSFETs should be fast, able to withstand high currents (in excess of 30A each if possible) and have the lowest possible Rds(on). The proposed On-Semiconductor?s MTP75N06 can withstand 75Amp and has a Rds(on) below 10 milliohm. This is important, because the lower this resistance is, the less power they are going to dissipate when switching with a square waveform. Another alternatives are MTP60N06, or the more popular BUZ11 and IRF540.

Although the schematics show a previous bipolar push-pull stage, you can also connect the gate resistor directly to the output of the controlling IC, leaving out the transistors, as the SG3525 is capable to drive up to 500 mA (theoretically), more than enough to switch the MOSFETs fast.

These MOSFETs should be fast, able to withstand high currents (in excess of 30A each if possible) and have the lowest possible Rds(on). …

Source:http://sound.westhost.com/project89.htm
Thank you.

Be the first to comment - What do you think? Posted by admin - September 24, 2007 at 6:13 pm

Categories: DC converter, Switching power supply Tags: dc converter ic, dual output power supply, SG3525, step up dc converters

PWM DC motor control with SG3525

This control circuit is ideal for the accurate control of DC motors as well as other applications like lighting levels and small heaters etc. The circuit converts a DC voltage into series of pulses, such that the pulse duration is directly proportion to the value of the DC voltage. The great advantage of such a circuit is that almost no power is lost in the control circuit.

This circuit protects against overload and short circuit, PWM range can be adjusted from 0-100%, PWM frequency is 100HZ-5KHZ adjustable. Operation voltage from +8V~ 35V, minimum current consumption is about 35mA. Maximum current can go up to 6.5A. Efficiency better than 90% at full load.

The functions of three trim pots are as follow:
VR1: setting the minimum output voltage
VR3: setting the maximum output voltage
VR2: setting the output frequency.
Source:http://home.att.net/~wzmicro/3525.html

Be the first to comment - What do you think? Posted by admin - September 12, 2007 at 9:26 pm

Categories: Electronic Control, Motor controller Tags: Motor controller, PWM-Speed-Motor, SG3525

POWER SUPPLY Switching 12V for CAR by SG3525

Switchmode Preamp Supply For Cars
DescriptionThe extreme simplicity of this design is thanks to the circuitry inside the SG3525 controller IC. The two outputs have dual switching transistors, and these can be used to create a full bridge forward converter switchmode supply with the absolute minimum of external parts. As shown in Figure 1, the supply is unregulated. While this may seem to be a fundamentally bad idea, the car supply is actually reasonably well regulated at 13.8V, and this means that the output of the supply will not fluctuate very much.

Since opamps are very tolerant of supply variations (especially if they are fairly low frequency), this means that the inductors that are used in nearly all switching converters can be eliminated. Inductors (and associated flyback diodes) must be used if the supply is regulated, and in the interests of simplicity, I did not want to go that way.