Secret Diagram: Regulator

Showing posts with label Regulator. Show all posts

Friday, 24 March 2017

LTM4620 – Dual 13A or Single 26A DC DC µModule Regulator with Integrated Heatsink

The LTM4620 is a dual 13A per output (or single 26A output) DC/DC μModule step-down regulator that delivers up to 100A when four devices are current shared. The LTM4620 is a complete DC/DC regulator system in a 15mm x 15mm x 4.41mm LGA package, including inductors, power stages and all control circuits. For optimum heat dissipation, an integrated top side heat sink removes heat quickly and evenly.

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Sunday, 19 March 2017

LDO Regulator

Recently the author had to adapt a standard circuit configuration (which often uses an npn bipolar) so as to operate as a low-dropout (LDO) regulator. The circuit shown here uses that rarity, a depletion-mode MOSFET to implement the LDO function. What to do when you have to derive an analogue supply voltage (close to +5 V) from an existing ‘digital’ 5-volt rail, ensuring sufficient decoupling between the two? One answer is to step up and then use a linear regulator to step back down. However, if around 4.5 volts will suffice then an alternative is a home-made LDO regulator. The circuit is usually a fairly standard shape typically a npn transistor (with base-current limiting resistor) is used.

Circuit diagram :

LDO-Regulator-Circuit Diagram

LDO Regulator Circuit Diagram

Initially, it would appear that this design suffices after all, the text books say the saturation voltage is around 0.2 V. Unfortunately, this is no longer true when the collector is tied directly to the positive supply. An enhancement-mode MOSFET suffers similar disadvantages: with the drain tied High you need greater than drain potential at the gate to achieve low RDS(on). Enter that seldom-used beast the depletion-mode MOSFET! Depletion-mode MOSFETS are ‘on’ even when V gs = 0, and you have to back-bias the gate to achieve an increase in channel resistance.In the circuit shown the BSS139, an NMOS depletion device, operates with the gate forward biased. With a load of 10 mA, the measured FET resistance was 38 ohms.

Author :Stephen Bernhoeft - Copyright : Elektor electronics

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Friday, 24 February 2017

Using IFR Voltage Regulator Circuit Diagram

The IFR EW a MOSFET transistor, such as transistor has higher feature high input impedance. In this circuit we used an IFR as transistor voltage regulator, which is not common, but it is very good to learn about their behavior in a circuit.

Using IFR Voltage Regulator Circuit Diagram

This voltage regulator circuit uses a MOSFET is
IRF4905 (Vdss =-55V, RDS (on) = 0.02ohm, Id =-74A),
but any other can be tested.

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Saturday, 3 December 2016

1 1 Regulator Handles Two Input Voltages Circuit Diagram

Regulator Handles Two Input Voltages circuit in Fig 1 supplies both 3.3 and 5V to transitional circuits that employ both the new 3.3V and older 5V devices. Additionally, because the regulator accepts either 3.3 or 5V inputs, you could plug it into either a new 3.3V system or an old 5V system.The circuit consists of two sections: a dc/dc converter and a double-pole, double-throw (dpdt) switch. The dpdt switch comprises a pair of dual n-channel MOSFETs (Q2 and Q3) and their associated high-side drivers.

Upon power-up, the comparator in IC2 determines the state of the circuit. The comparator’s output, IC2 pin 6, goes to the input of the MOSFET driver, IC1. The driver internally generates a gatedrive voltage 8.8V above the device’s supply voltage. This high voltage drives the appropriate MOSFETs in Q2 and Q3.

IC2 is also the heart of a flying-capacitor, buck/boost dc/dc converter. Unlike other switching-regulator schemes, this topology needs no transformers. Transistor Q1 controls this section’s output voltage, VS. When VIN is at 5V, Q1 is off, forcing the section to operate as a step-down converter. In this mode, the section produces 3.3V, which goes to the output through Q3B. Also in this mode, 5V power goes directly through Q2A, and Q2B and Q3A are both off.

When VIN is 3.3V, IC1 turns on Q1, shorting out the 140-kΩ resistor and forcing the dc/dc-converter section into step-up mode. In this mode the converter section generates 5V at VS, powering the 5V output via Q2B. Also in this mode, 3.3V goes directly from the circuit’s input to the output via Q3A. Q2A and Q3B are both off.No-load quiescent current consumption is approximately 500 μA.

Lower-frequency converters would reduce power consumption at the expense of a larger inductor. The efficiency of the dc/dc-converter section is 73% in either mode. But because this power accounts for only half of the circuit’s output power, the circuit’s overall efficiency is approximately 80% with VIN=3.3V and 86% with VIN=5V.

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Monday, 14 November 2016

Temperature Regulator with TIP122 Circuit Diagram

For best efficiency,make good thermal contact between the 40 ohm resistor,the TIP 122,the 3 diodes and the temperature controlled entity , the components all give off heat. We have some minor changes to the draft Roy. Roy A 4.7V zener is used in its original design and a resistor network, a range of operating temperatures of 188 degrees Kelvin to 243 Kelvin degrees C or -85 to -30 C.

Temperature Regulator Circuit with TIP122

This is fine in Cryocam Roy, but I’m afraid that many of our camera cookbook may not be able to reach a maximum temperature of Roy. That and the fact that related to the Zener 4.7V difficult to replace me with Roy Z 5.1V zener with more accessible. This diode is available off the shelf at Radio Shack. I supply the resistor network on a range of 190 K to 270 K or -83 C to -3 C I believe that most of our cameras can be maintained to -3 C and I doubt that all our cameras in a position are to be attained – 83 C, so I think that this area should be good enough coverage. I chose to use a 100k pot at some point, because I’m going to the plate with a dual digital potentiometer DS1267 replace. I do not allow for a distance, using Win245 software controllable temperature control and the 100K pot is the control loop is working is to be updated very easily. I intend to use the pot on the remaining DS1267 to replace R43 on the board pre-amp. This allows a selectable gain control software for the camera cookbook. More later.

I would recommend the maximum TEC voltage regulator and leave it there. The circuit temperature controller does the rest. You may want to perform delete on the part of the adjustment of supply voltage and tie the totally positive TEC voltage directly at the outlet of the resistors R1 and R2 in parallel with power supply stocks cookbook. There is much room is available for experiment. Roy says that his power TEC does not need to precisely controlled tension, but also be filtered and have less than 10% ripple. So, I think you no harm by not following the proportion of the supply voltage regulation will do Peltier.

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