Analog Devices LT3081, LT8612, LT3092 | Demoboard DC2132A

Description

DC2132A is a 24V 3A constant voltage, constant current bench supply. It regulates any output voltage from 0V to 24V and any output current from 0A to 3A. It runs from 10V to 40V input although the output voltage should remain 5V or more below the input voltage.

The LT®8612 step-down regulator is followed by two parallel LT®3081 linear regulators for a combination of low output ripple, high bandwidth and easy-to-adjust output voltage and current limits. The LT8612 is configured in pulseskipping operation and its output voltage is regulated to roughly 1.7V above the output voltage of the LT3081. The LT3081 SET and ILIM pins are connected to potentiometers that act as adjustable knobs on the PCB for voltage and current limit respectively.

The LT®3092 current source is used to deliver current to power the adjustable resistance of the voltage limit knob (potentiometer). That voltage directly sets the output voltage of the LT3081. The maximum output voltage can be set to three settings: 24V, 15V and 5.5V with the shunt position on JP1. The setting should be changed according to the choice of input voltage. A 36V, 24V, or 12V AC/DC converter can be used to power this supply (as well as any DC voltage between 10V and 40V.) If input voltagelimits maximum output voltage, then it is recommended to adjust the maximum output voltage to get the full range of the adjustment knob for best resolution.

DC2132A operates to 0V and 0A. It is short-circuit proof. With very small output capacitance, the short-circuit spike is hundreds of times shorter in duration than commonly used and expensive laboratory bench power supplies.With the LT3081s in parallel on the output of this supply, small output capacitance makes this possible. Only 30μF is needed on the output of each LT3081. The LT3081 provides very low output ripple and short-circuit robustness.

An ON/OFF switch turns the converter and its components on and off. A green indicator LED tells if the circuit is on or not. Two TEMP turrets and an IMON turret provide readouts of the LT3081 IC temperatures and the benchsupply output current.

The LT3081, LT8612, and LT3092 data sheets give complete descriptions of the devices, operation and applications information. The data sheet must be read in conjunction with this demo manual for DC2132A. The LT3081ER is assembled in a 7-lead plastic DD (R) package with a thermally enhanced VOUT tab and with θJA = 15ºC/W. Proper board layout is essential for maximum thermal performance. See the the Layout Considerations section in the data sheet.

Features

Remarks:L1=5.5uH L2=470uH Used Refer page no.9

More information

• Datasheet
• IC product information