hip6015cb Intersil Corporation, hip6015cb Datasheet - Page 5

• Manufacturer Part Number: hip6015cb
• Description: Buck Pulse-width Modulator Pwm Controller And Output Voltage Monitor
• Manufacturer: Intersil Corporation

GND (Pin 11)
Signal ground for the IC. All voltage levels are measured with
respect to this pin.
PGOOD (Pin 12)
PGOOD is an open collector output used to indicate the
status of the converter output voltage. This pin is pulled low
when the converter output is not within 10% of the
DACOUT reference voltage. Exception to this behavior are
the cases where the VID pins combination yield a 0V
converter output; in these cases PGOOD asserts a high
level.
PHASE (Pin 13)
Connect the PHASE pin to the upper MOSFET source. This
pin is used to monitor the voltage drop across the MOSFET
for over-current protection. This pin also provides the return
path for the upper gate drive.
UGATE (Pin 14)
Connect UGATE to the upper MOSFET gate. This pin
provides the gate drive for the upper MOSFET.
BOOT (Pin 15)
This pin provides bias voltage to the upper MOSFET driver.
A bootstrap circuit may be used to create a BOOT voltage
suitable to drive a standard N-Channel MOSFET.
NC (Pin 16)
No connection.
NC (Pin 17)
No connection.
V
Provide a 12V bias supply for the chip to this pin.
OVP (Pin 19)
The OVP pin can be used to drive an external SCR in the
event of an overvoltage condition. Output rising 15% more
than the DAC-set voltage triggers a high output on this pin
and disables PWM gate drive circuitry.
R
This pin provides oscillator switching frequency adjustment.
By placing a resistor (R
200kHz switching frequency is increased according to the
following equation:
Conversely, connecting a pull-up resistor (R
to V
following equation:
Fs 200kHz
Fs 200kHz
CC
T
(Pin 20)
CC
(Pin 18)
reduces the switching frequency according to the
+
–
-------------------- -
R
-------------------- -
R
5 10
4 10
T
T
k
k
7
6
T
) from this pin to GND, the nominal
(R
(R
T
T
to 12V)
to GND)
5
T
) from this pin
HIP6015
Functional Description
Initialization
The HIP6015 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. The POR monitors the bias
voltage at the V
OCSET pin. The level on OCSET is equal to V
voltage drop (see over-current protection). The POR function
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.
Soft Start
The POR function initiates the soft start sequence. An
internal 10 A current source charges an external capacitor
(C
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
amplifier (COMP pin) controls the converter’s output voltage.
At t
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 t
the clamp on the reference input controls the output voltage.
This is the interval between t
voltage exceeds the DACOUT voltage and the output
voltage is in regulation. This method provides a rapid and
controlled output voltage rise. The PGOOD signal toggles
‘high’ when the output voltage (V
DACOUT. The 2% hysteresis built into the power good
comparators prevents PGOOD oscillation due to nominal
output voltage ripple.
0V
0V
0V
SS
1
) on the SS pin to 4V. Soft start clamps the error
in Figure 3, the SS voltage reaches the valley of the
SOFT-START
FIGURE 3. SOFT START INTERVAL
(1V/DIV.)
CC
t
1
SS
pin and the input voltage (V
IN
= 0.1 F. Initially the clamp on the error
TIME (5ms/DIV.)
and V
2
(2V/DIV.)
PGOOD
. With sufficient output voltage,
2
t
2
and t
CC
SEN
are equivalent and the
3
in Figure 3. At t
pin) is within 5% of
t
3
CC
IN
OUTPUT
VOLTAGE
(1V/DIV.)
IN
threshold
less a fixed
) on the
3
the SS