RT8113 RICHTEK [Richtek Technology Corporation], RT8113 Datasheet - Page 16

• Manufacturer Part Number: RT8113
• Description: Single Phase VR11.1 PWM Controller with 7-bit VID
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT8113
Output Current Sensing
The RT8113 provides a low input offset current-sense
amplifier (CSA) to monitor the output current. The output
current of CSA (I
current protection. In this inductor current sensing
topology, R
below :
Then the output current of CSA will follow the equation
below :
www.richtek.com
16
I =
DCR
X
L
I x DCR - V
L
= R x C
S
S
and C
S
X
OFS-CSA
) is used for load line control and over-
S
must be set according to the equation
+ 700n x R
R
I
X
CSA: Current Sense Amplifier
CSN
(
CSP
Figure 7. Circuit for Current Sensing
+ R - R
V
S
700nA
OFS_CSA
700nA
CSN
+
)
-
UGATE
+
-
PHASE
LGATE
BOOT
700nA is a typical value of the CSA input offset current.
V
the RT8113 is smaller than +/- 1.5mV. Usually, “V
+ 700n x (R
light load and the equation can be simplified as the equation
below :
I =
X
OFS-CSA
ISN
ISP
I x DCR
L
R1
R
C1
R
CSN
is the input offset voltage of CSA. V
CSN
V
R
IN
CSP
CSP
+ R
R2
C2
S
- R
R
L
CSN
S
)” is negligible except at very
DCR
C
S
DS8113-02 April 2011
OFS-CSA
OFS-CSA
of