Analog Devices DC371 User manual

Quick Start Guide for DC371
By Wei Chen
DC371 is an IMVP2 compatible power supply for powering the Intel mobile Tualatin
processor. The input voltage is 7–21V, the output voltage is programmed by the 5-bit
VID which is compatible with the IMVP2 spec. The circuit is designed to deliver 23A
continuous current. The demo board has an on-board dynamic load tester to facilitate the
dynamic load test.
Quick Start Guide
Refer to Figure 2 for proper measurement equipment setup and follow the procedure
below:
1. Connect a 21V bench supply to VIN and GND pins, a 5V supply to 5V pin and GND
pin, and a 3.3V supply to 3.3V pin and GND. All supplies must be off.
2. Connect an electronic load to VCORE and GND pins using a wire gauge suitable for
23A. Preset load current to 0A.
3. Initial jumper setup for performance mode operation:
JP7
Short to 5V side
JP11
Short
VID4 VID3 VID2 VID1 VID0
Short Short Open Open Open
DPSLP# VRON DPSLPVR GMUXSEL
Short Open Open Short
4. Apply 21V, then 5V and 3.3V
5. Short Jumper VRON. Measure VCORE = 1.380 ~ 1.420 V
6. Apply load current of 23A, measure voltage across C15 to be: 1.288 ~ 1.328V
VIN = 21V ± 0.5V, IIN < 2A
7. Change load to 0A
8. Open Jumper DPSLP#, measure VCORE = 1.318~1.358V
9. Decrease VIN from 21V to 14V, change jumpers for battery mode operation:
VID4 VID3 VID2 VID1 VID0
Short Open Open Short Short
DPSLP# VRON DPSLPVR GMUXSEL
Short Short Open Open
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10. Measure VCORE = 1.115 ~1.155V
11. Open Jumper DPSLP#, measure VCORE = 1.064 ~ 1.104V
12. Short Jumper DPRSLPVR, set VID jumpers for deeper sleep mode operation:
VID4 VID3 VID2 VID1 VID0
Open Short Open Short Open
13. Measure VCORE = 0.82~0.88V
14. Short Jumper GMUXSEL, measure VCORE = 0.82~ 0.88V
Dynamic Load Transient Tests
1. After the output voltage reaches the preset values, apply the load current equal to the
minimum load current of the load step test.
2. Apply ±12V supplies to +12V, PGND and –12V pins. Then remove jumper JP11.
3. Use the oscilloscope to test the output step currents from BNC connector “IO”.
Adjust potentiometers R44, R45 and R49 to vary the slew down slope, slew up slope
and step amplitudes (respectively) of the load current change.
4. Measure the output voltage directly across Cap C15.
While doing the load transient tests, one should make sure that the input bench supply
should have sufficient decoupling capacitance. The following waveform is taken in
the performance mode: VIN = 21V, VID = 1.4V, GMUSEL = DPSLP# = 1,
DPRSLPVR = 0. The minimum load current is 8A, and the maximum load current is
23A. The minimum output voltage is 1.30V and the maximum output voltage is
1.39V.
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Figure 1. Timing
+
–
+
–
+–
+
–
+
–+
–
+
–
+
–
+
–
LOAD
+–
21V
5V
3.3V
E1
3.3V
VID4 JP6 VID3 JP5 VID2 JP4 VID1 JP3 VID0 JP2
DPSLP# VRON DPRSLPVR GMUXSEL
E3
5V JP7
J1
Vin Inductor
J2
Gnd
J3
Vcore
J4
Gnd
Pwrgood
E2
E4
+12V
+12V –12V
E6
PGND
E5
–12V
Transient Load Tester
Bench Supply
Vin Vcore
C15
R49 R45 R44
J5
IO
JP11
LTC3714EG
Intel's Notebook Processor
Power Supply
Demo Circuit DC371A
Figure 2. Proper Measurement Equipment Setup