ir3502b International Rectifier Corp., ir3502b Datasheet - Page 18

• Manufacturer Part Number: ir3502b
• Description: Xphase3 Control Ic
• Manufacturer: International Rectifier Corp.

Current Monitor (IMON)
The control IC generates a current monitor signal IMON using the VDRP voltage and the VDAC reference, as
shown in Figure 10. This voltage is thermally compensated for the inductor DCR variation. The voltage at this pin
reports the average load current information without being referenced to VDAC. The slope of the IMON signal with
respect to the load current can be adjusted with the resistors RTCMP2 and RTCMP3. The IMON signal is clamped
at 1.03V in order to facilitate direct interfacing with the CPU.
ENABLE
VDAC
VRRDY
(12V)
VCC
SS/DEL
EAOUT
VOUT
1.1V
Page 18 of 38
3.92V
4.0V
1.4V
3V
START DELAY (TD1)
Figure 9 Start-up sequence of converter with boot voltage
Figure 10 Current report signal (IMON) implementation
VDAC
+
-
VDAC
Buffer
VOSEN-
VDRP
Control IC
200k
100k
SOFT START
TIME (TD2)
200k
200k
200k
-
+
200k
+
-
Thermal
Comp
Amplifier
VDRP
Buffer
VID SAMPLE
TIME (TD3)
1.03
0
+
VID
-
VDRP
VN
DAC_BUFF
IMON
TD4
IIN
From Phase ICs
VRRDY DELAY
TIME (TD4+TD5)
RTCMP1
RTCMP2
TD5
RTCMP3
RTHERM
NORMAL OPERATION
IR3502B
V3.2