isl62883c Intersil Corporation, isl62883c Datasheet - Page 15

• Manufacturer Part Number: isl62883c
• Description: Multiphase Pwm Regulator For Imvp-6.5? Mobile Cpus And Gpus
• Manufacturer: Intersil Corporation

Start-up Timing
With the controller's V
threshold, the start-up sequence begins when VR_ON
exceeds the 1.1V logic high threshold. Figure 10 shows
the typical start-up timing when the ISL62883C is
configured for CPU VR application. The ISL62883C uses
digital soft-start to ramp-up DAC to the boot voltage of
1.1V at about 2.5mV/µs. Once the output voltage is
within 10% of the boot voltage for 13 PWM cycles
(43µs for frequency = 300kHz), CLK_EN# is pulled low
and DAC slews at 5mV/µs to the voltage set by the VID
pins. PGOOD is asserted high in approximately 7ms.
Similar results occur if VR_ON is tied to V
soft-start sequence starting 120µs after V
POR threshold.
Figure 11 shows the typical start-up timing when the
ISL62883C is configured for GPU VR application. The
ISL62883C uses digital soft start to ramp up DAC to the
voltage set by the VID pins. The slew rate is 5mV/µs
when there is DPRSLPVR = 0, and is doubled when there
is DPRSLPVR = 1. Once the output voltage is within 10%
of the target voltage for 13 PWM cycles (43µs for
frequency = 300kHz), CLK_EN# is pulled low. PGOOD is
asserted high in approximately 7ms. Similar results occur
if VR_ON is tied to V
starting 120µs after V
FIGURE 10. SOFT-START WAVEFORMS FOR CPU VR
FIGURE 11. SOFT-START WAVEFORMS FOR GPU VR
CLK_EN#
CLK_EN#
PGOOD
PGOOD
VR_ON
VR_ON
VDD
DAC
VDD
DAC
APPLICATION
APPLICATION
120µs
800µs
DD
SLEW
RATE
13 SWITCHING
DD
2.5mV/µs
DD
, with the soft-start sequence
90%
crosses the POR threshold.
15
CYCLES
voltage above the POR
13 SWITCHING
VID COMMAND
VOLTAGE
90%
CYCLES
5mV/µs
Vboot
~7ms
COMMAND
DD
VOLTAGE
DD
~7ms
VID
, with the
crosses the
ISL62883C
Voltage Regulation and Load Line
Implementation
After the start sequence, the ISL62883C regulates the
output voltage to the value set by the VID inputs per
Table 1. The ISL62883C will control the no-load output
voltage to an accuracy of ±0.5% over the range of
0.75V to 1.5V. A differential amplifier allows voltage
sensing for precise voltage regulation at the
microprocessor die.
VID6 VID5 VID4 VID3 VID2 VID1 VID0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
TABLE 1. VID TABLE
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
March 18, 2010
FN7557.1
1.5000
1.4875
1.4750
1.4625
1.4500
1.4375
1.4250
1.4125
1.4000
1.3875
1.3750
1.3625
1.3500
1.3375
1.3250
1.3125
1.3000
1.2875
1.2750
1.2625
1.2500
1.2375
1.2250
1.2125
1.2000
1.1875
1.1750
1.1625
1.1500
1.1375
1.1250
1.1125
(V)
V
O