ffd

What i am making here is a USB lock with smartcard key. The idea is that a phonecard reader made with a PIC micro will be able to store a number of different phonecards into memory. Whenever one of these cards is inserted into the slot, it will activate a 4-ports USB On/Off switch. If the card is removed, the USB ports will be de-activated. [ ]

ADJUSTABLE 1.5A STEP DOWN 1.5MHz SWITCHING REGULATOR ELECTRONIC DIAGRAM However, an Adjustable 1.5A Step Down 1.5 MHz switching regulator circuit can also be used to overcome such problem. It uses ST1S03 step down DC-DC converter. The ST1S03 can also be used to power low-voltage digital core in HDD application . With input voltage range 3V to 16V, the ST1S03 can gives current up to 1.5A. The circuit can use tiny surface-mount components due to an high switching frequency (1.5 MHz). Resistor divider is used to set the output voltage value. Components needed to build the divided are capacitors (2 pieces), schottky diode (1 piece), and inductor (1 piece).

The circuit described here is mostly aimed at development engineers who are looking for an economical step-down converter which offers a wide input voltage range. As a rule this type of circuit employs a step-down converter with integrated switching element. However, by using a more discrete solution it is possible to reduce the total cost of the step-down converter, especially when manufacturing in quantity. The TL5001A is a low-cost PWM controller which is ideal for this project. The input voltage range for the step-down converter described here is from 8 V to 30 V, with an output voltage of 5 V and a maximum output current of 1.5 A. Low-Cost Step-Down Converter With Wide Input Voltage Range Circuit Diagram When the input voltage is applied the PWM output of IC1 is enabled, taking one end of the voltage divider formed by R1 and R2 to ground potential. The current through the voltage divider will then be at most 25 mA: this value is obtained by dividing the maximum input voltage (30 V...