DC1051A Analog Devices

DEMO MANUAL DC1051A LTC4217 2A Integrated Hot Swap Controller Description Demonstration circuit 1051A includes two separate circuits to the sense voltage and it may be converted to a voltage for performance evaluation of the LTC 4217 2A integrated signal with an appropriate resistor. Hot Swap controller. This integrated circuit includes The current limit may be reduced by placing an external a power MOSFET to save board area and to minimize resistor between GND and the ISET pin. external component count. The standard version of the The DC1051A schematic allows the LTC4217 to operate in controller (LTC4217) is intended to operate with 2.9V to turn-on and turn-off modes as well as in the steady-state 26.5V rails, while the LTC4217-12 has internal adjustment mode with different loads, and in the fault mode. for 12V applications. The LTC4217 features an overtemperature protection The circuit of DC1051A located on the upper board area circuit, and protects the load from overvoltage and un- is assembled with the LTC4217 configured for operation dervoltage conditions. with a 24V rail. The lower circuit includes the LTC4217-12. Current limit features of both circuits are identical, with Design files for this circuit board are available at 5% accuracy and a distinctive foldback property. DEMO MANUAL DC1051A o p The LTC4217 is suited for low voltage applications such as Adjustable inrush current control hot board insertion and removal. The LTC4217 has a rich Load current monitoring set of features to support Hot Swap applications including: Adjustable current limit timer before power is turned Integrated power MOSFET for a compact Hot Swap off solution Power good signaling 2% accurate undervoltage and overvoltage protection Adjustable 5% accurate current limit Quick s p D Demonstration circuit 1051 is easy to set up to evaluate 6. Use a 900F capacitive load to demonstrate that power the performance of the LTC4217. Refer to Figure 1 for up mode completes successfully. Use a current probe the proper measurement equipment setup and follow the to verify that inrush current is limited initially by the procedure below. foldback characteristic and later by the low output voltage slew rate. For the 24V circuit: 7. Use a 3500F capacitive load to demonstrate that the 1. Place jumpers in the following positions: part not only enters into the current limit state but JP1 FAULT Signal operates in this state until the timer period expires. JP2 AUX UV ON For the 12V circuit: 2. With power off, connect the 24V power supply terminals 8. Place jumpers in the following positions: to the 24V (E1) and GND (E3) turrets. IN JP3 FAULT Signal 3. Turn on the 24V supply and verify the output voltage JP4 AUX UV ON between the V (E7) and GND (E8) turrets. Two green OUT LEDs, 24V (D2) and V (D6), should light up. 9. With power off, connect the 12V power supply terminals IN OUT to the 12V (E9) and GND (E12) turrets. IN 4. Check the current limit using an electronic or resistive load. It should be in the range of 1.9A to 2.1A if an 10. Turn on the 12V supply and verify the output voltage overcurrent condition occurs while the output is high at the V (E15) and GND (E16) turrets. Green LEDs OUT (after powering up properly). If the output is shorted 12V (D8) and V (D12) should light. IN OUT initially, the load current will be limited in the range of 11. Check the current limit using an electronic or resis- 0.475A to 0.525A due to the foldback characteristic. tive load. It should be in the range of 1.9A to 2.1A. Current may be monitored on the IMON test point During this measurement verify the current monitor during this measurement. The IMON signal scale is performance. The monitor signal related to the current 1V/A. limit level should be 1.9V to 2.1V. An overcurrent condition is indicated by red LED FAULT 12. Check the output voltage slew rate with an oscilloscope, (D3) and red LED PG (D4). without a load connected. It should take from 21ms 5. Check the output voltage slew rate with an oscilloscope, to 80ms for the output voltage to rise to 12V. without a load connected. It takes 43.6ms to 160ms for the output voltage to power up completely. dc1051af 2 ure roce tart rinciples perating