ISL6160EVAL2 Intersil, ISL6160EVAL2 Datasheet - Page 5

• Manufacturer Part Number: ISL6160EVAL2
• Description: EVAL BOARD FOR ISL6160/HIP6006
• Manufacturer: Intersil

Specifications of ISL6160EVAL2

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 5V
• Current - Output: 3.5A
• Voltage - Input: 5V, 12V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: HIP6006, ISL6160
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Frequency - Switching: -

LGATE (Pin 12)
Connect LGATE to the lower MOSFET gate. This pin
provides the gate drive for the lower MOSFET.
PVCC (Pin 13)
Provide a bias supply for the lower gate drive to this pin.
VCC (Pin 14)
Provide a 12V bias supply for the chip to this pin.
Functional Description
Initialization
The HIP6006 automatically initializes upon receipt of power.
Special sequencing of the input supplies is not necessary.
The Power-On Reset (POR) function continually monitors
the input supply voltages and the enable (EN) pin. The POR
monitors the bias voltage at the VCC pin and the input
voltage (V
equal to V
protection). With the EN pin held to V
initiates soft start operation after both input supply voltages
exceed their POR thresholds. For operation with a single
+12V power source, V
+12V power source must exceed the rising V
before POR initiates operation.
The Power-On Reset (POR) function inhibits operation with
the chip disabled (EN pin low). With both input supplies
above their POR thresholds, transitioning the EN pin high
initiates a soft start interval.
Soft Start
The POR function initiates the soft start sequence. An internal
10µA current source charges an external capacitor (C
the SS pin to 4V. Soft start clamps the error amplifier output
(COMP pin) and reference input (+ terminal of error amp) to
the SS pin voltage. Figure 3 shows the soft start interval with
C
pin) controls the converter’s output voltage. At t1 in Figure 3,
the SS voltage reaches the valley of the oscillator’s triangle
wave. The oscillator’s triangular waveform is compared to the
ramping error amplifier voltage. This generates PHASE
pulses of increasing width that charge the output capacitor(s).
This interval of increasing pulse width continues to t2. With
sufficient output voltage, the clamp on the reference input
controls the output voltage. This is the interval between t2 and
t3 in Figure 3. At t3 the SS voltage exceeds the reference
voltage and the output voltage is in regulation. This method
provides a rapid and controlled output voltage rise.
SS
= 0.1µF. Initially the clamp on the error amplifier (COMP
IN
IN
) on the OCSET pin. The level on OCSET is
Less a fixed voltage drop (see over-current
IN
and V
5
CC
are equivalent and the
CC
, the POR function
CC
threshold
SS
) on
HIP6006
Over-Current Protection
The over-current function protects the converter from a
shorted output by using the upper MOSFETs on-resistance,
r
converter’s efficiency and reduces cost by eliminating a
current sensing resistor.
The over-current function cycles the soft-start function in a
hiccup mode to provide fault protection. A resistor (R
programs the over-current trip level. An internal 200µA
(typical) current sink develops a voltage across R
is reference to V
MOSFET (also referenced to V
across R
start sequence. The soft-start function discharges C
a 10µA current sink and inhibits PWM operation. The soft-
start function recharges C
with the error amplifier clamped to the SS voltage. Should an
overload occur while recharging C
inhibits PWM operation while fully charging C
DS(ON)
0V
0V
15A
10A
4V
2V
5A
0A
0V
to monitor the current. This method enhances the
OCSET
FIGURE 4. OVER-CURRENT OPERATION
FIGURE 3. SOFT-START INTERVAL
, the over-current function initiates a soft-
IN
SOFT-START
(1V/DIV)
. When the voltage across the upper
t1
TIME (5ms/DIV)
SS
TIME (20ms/DIV)
, and PWM operation resumes
IN
t2
) exceeds the voltage
SS
OUTPUT
VOLTAGE
(1V/DIV)
, the soft start function
t3
SS
OCSET
to 4V to
SS
OCSET
with
that
)