HIP6302CB-T Intersil, HIP6302CB-T Datasheet - Page 11

• Manufacturer Part Number: HIP6302CB-T
• Description: IC CONTROLLER PWM BUCK 16-SOIC
• Manufacturer: Intersil

Specifications of HIP6302CB-T

• Pwm Type: Controller
• Number Of Outputs: 2
• Frequency - Max: 305kHz
• Voltage - Supply: 4.75 V ~ 5.25 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 16-SOIC (3.9mm Width)
• Frequency-max: 305kHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Duty Cycle: -
• Other names: HIP6302CB-TR

Current Sensing and Balancing
Overview
The HIP6302 samples the on-state voltage drop across each
synchronous rectifier FET, Q2, as an indication of the
inductor current in that phase, see Figure 7. Neglecting AC
effects (to be discussed later), the voltage drop across Q2 is
simply r
inductor current, is 1/2 of the total current (I
The voltage at Q2’s drain, the PHASE node, is applied to the
R
ISEN pin. This pin is held at virtual ground, so the current
through R
The I
following functions:
Over-Current, Selecting R
The current detected through the R
with the current detected in the other channel. The averaged
1. Detection of an over-current condition
2. Reduce the regulator output voltage with increasing load
3. Balance the I
ISEN
current (droop)
ISEN
FB
resistor to develop the I
DS(ON)
ISEN
current provides information to perform the
CURRENT
TO OVER
REFERENCE
AMPLIFIER
FIGURE 7. SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM SHOWING CURRENT AND VOLTAGE SAMPLING
(Q2) x inductor current (I
is I
R
ERROR
+
-
TRIP
FB
L
DAC
R
L
currents in the two phases
IN
x r
C
COMPARATOR
c
DS(ON)
CHANNELS
TO OTHER
COMP
11
(Q2) / R
GENERATOR
ISEN
SAWTOOTH
ISEN
CORRECTION
+
+
-
ISEN
current to the HIP6302
DIFFERENCE
-
ISEN
L
resistor is averaged
). Note that I
REFERENCE
-
.
LT
+
).
AVERAGING
COMPARATOR
+
-
L
, the
HIP6302
HIP6302
HIP6302
CURRENT
SENSING
CURRENT
SENSING
FROM
OTHER
CHANNEL
CIRCUIT
PWM
current is compared with a trimmed, internally generated
current, and used to detect an over-current condition.
The nominal current through the R
50µA at full output load current, and the nominal trip point for
over-current detection is 165% of that value, or 82.5µA.
Therefore, R
For a full load of 25A per phase, and an r
4mΩ, R
The over-current trip point would be 165% of 25A, or ~ 41A
per phase. The R
over-current trip point, but it is suggested to stay within ±25%
of nominal.
Droop, Selection of R
The average of the currents detected through the R
resistors is also steered to the FB pin. There is no DC return
path connected to the FB pin except for R
current creates a voltage drop across R
increases the apparent V
current, causing the system to decrease V
balance at the FB pin. This is the desired “droop” voltage
used to maintain V
conditions.
PWM
ISEN
I
SEN
ISEN
= 2kΩ .
ONLY ONE OUTPUT
HIP6601
ISEN
= I
CORE
L
STAGE SHOWN
R
x r
ISEN
value can be adjusted to change the
CORE
within limits under transient
DS(ON)
IN
INDUCTOR
Q2
CURRENT
CHANNEL
V
IN
OTHER
FROM
voltage with increasing load
Q1
(Q2)/50µA.
ISEN
PHASE
L
I
01
L
IN
resistor should be
DS(ON)
IN
. This drop
CORE
, so the average
December 27, 2004
V
CORE
to maintain
(Q2) of
ISEN
FN4766.3