The circuit is a MOSFET based linear voltage regulator with a voltage drop of as low as 60 mV at 1 ampere. Drop of a fewer millivolts is possible with better MOSFETs having lower RDS(on) resistance. The circuit in Fig. 1 uses 15V-0-15V secondary from a step-down transformer and employs an n-channel MOSFET IRF 540 to get the regulated 12V output from DC input, which could be as low as 12.06V. The gate drive voltage required for the MOSFET is generated using a voltage doubler circuit consisting of diodes D1 and D2 and capacitors C1 and C4. To turn the MOSFET fully on, the gate terminal should be around 10V above the source terminal which is connected to the output here. The voltage doubler feeds this voltage to the gate through resistor R1. Adjustable shunt regulator TL431 (IC2) is used here as an error amplifier, and it dynamically adjusts the gate voltage to maintain the regulation at the output. With adequate heatsink for the MOSFET, the circuit can provide up to 3A output at slightly elevated minimum voltage drop.
Trimpot VR1 in the circuit is used for fine adjustment of the output voltage. Combination of capacitor C5 and resistor R2 provides error-amplifier compensation. The circuit is provided with a short-circuit crow-bar protection to guard the components against over-stress during accidental short at the output. This crow-bar protection will work as follows: Under normal working conditions, the voltage across capacitor C3 will be 6.3V and diode D5 will be in the off state since it will be reverse-biased with the output voltage of 12V. However, during output short-circuit condition, the output will momentarily drop, causing D5 to conduct and the opto-triac MOC3011 (IC1) will get triggered, pulling down the gate voltage to ground, and thus limiting the output current. The circuit will remain latched in this state, and input voltage has to be switched off to reset the circuit. The circuit shown in Fig. 2 follows a similar scheme. It can be utilised when the regulator has to work from a DC rail in place of 15V-0-15V AC supply. The gate voltage here is generated using an LM555 charge pump circuit as follows: When 555 output is low, capacitor C2 will get charged through diode D1 to the input voltage. In the next half cycle, when the 555 output goes high, capacitor C3 will get charged to almost double the input voltage. The rest of the circuit works in a similar fashion as the circuit of Fig. 1. These circuits above will help reduce power-loss by allowing to keep lower input voltage range to the regulator during initial design or even in existing circuits. This will keep the output regulated with relatively low input voltage compared to the conventional regulators. The minimum voltage drop can be further reduced using low RDS(on) MOSFETs or by paralleling them.
Just think of voltage regulators, the beefier types of CPU and microcontroller, carrying a lot of current, but also devices like power LEDs. To get rid ... Because of this construction it is not possible to manufacture PCBs having
Electronics EETimes (registration) The CDM10V reduces the component count and PCB space needed for dimming in LED lighting applications by up to 70 percent. Infineon's CDM10V is the industry's first single-chip lighting interface IC capable
Electropages (blog) Latest from Linear is the LTC4380, an ultralow quiescent current (IQ) surge stopper, providing compact over-voltage and over-current protection for always-on 4V to 72V electronics in automotive, industrial and avionics sy
- global industry analysis 2020On the basis of , the global market for semiconductors for alternative energy can be given by Microcontroller (MCU), Analog , Advanced Mixed Signals, Digital Signal Processing, Advanced Power Conversion ICs <
Electronic Design Wolfspeed demonstrated a board that enables power electronics designers to quickly evaluate the performance of 900-V C3M in a surface-mount 7L-D2PAK package. The company also displayed a three-phase power evaluation unit th
In addition to fundamental power transistor specifications such as input voltage, on-resistance, and output current ratings, this tool provides a full range of specifications needed to make the best component selection for given conditions
intelligent power modules to ThalesLeveraging its HADES2 isolated gate driver (which incorporates years of development in driving SiC transistors), it combines advanced packaging , enabling reliable operation of power modules in extreme con
PR Newswire (press release) Ltd New 650V Half-Bridge Evaluation BoardTEL AVIV, Israel, April 14, 2016 /PRNewswire/ -- VisIC is pleased to announce its new Half-Bridge Evaluation Board using its VT15R65A GaN Power ALL Switch (Advanced Lo
Business Wire (press release) BUSINESS WIRE)--Power Integrations (Nasdaq: POWI), the leader in high-voltage integrated for energy-efficient power conversion, today announced its InnoSwitch™-CE ICs, a new clade of its InnoSwitch family