HIP6302VCB Intersil, HIP6302VCB Datasheet - Page 17

• Manufacturer Part Number: HIP6302VCB
• Description: IC CTRLR PWM MULTIPHASE 16-SOIC
• Manufacturer: Intersil

Specifications of HIP6302VCB

• Pwm Type: Controller
• Number Of Outputs: 4
• Frequency - Max: 336kHz
• 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: 336kHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Duty Cycle: -

single channel’s ripple current is approximtely calculated in
Equation 8:
The current from multiple channels tend to cancel each other
and reduce the total ripple current. Figure 14 gives the total
ripple current as a function of duty cycle, normalized to the
parameter
the total ripple current from the number of channels and the
duty cycle, multiply the y-axis value by
Small values of output inductance can cause excessive
power dissipation. The HIP6301V and HIP6302V are
designed for stable operation for ripple currents up to twice
the load current. However, for this condition, the RMS
current is 115% above the value shown in “MOSFET
Selection and Considerations” on page 17. With all else
fixed, decreasing the inductance could increase the power
dissipated in the MOSFETs by 30%.
Input Capacitor Selection
The important parameters for the bulk input capacitors are
the voltage rating and the RMS current rating. For reliable
operation, select bulk input capacitors with voltage and
current ratings above the maximum input voltage and
largest RMS current required by the circuit. The capacitor
voltage rating should be at least 1.25x greater than the
maximum input voltage and a voltage rating of 1.5x is a
conservative guideline. The RMS current required for a
multi-phase converter can be approximated with the aid of
Figure 15.
ΔI
=
V
------------------------------- -
1.0
0.8
0.6
0.4
0.2
IN
F
FIGURE 14. RIPPLE CURRENT vs DUTY CYCLE
0
SW
–
0
V
(
×
Vo
OUT
L
3-CHANNEL
)
⁄
×
(
LxF
V
--------------- -
0.1
V
OUT
4-CHANNEL
IN
SW
)
DUTY CYCLE (V
at zero duty cycle. To determine
0.2
17
SINGLE
CHANNEL
2-CHANNEL
0.3
O
(
/V
Vo
IN
)
)
⁄
(
LxF
0.4
SW
)
.
(EQ. 8)
0.5
First determine the operating duty ratio as the ratio of the
output voltage divided by the input voltage. Find the current
multiplier from the curve with the appropriate power
channels. Multiply the current multiplier by the full load
output current. The resulting value is the RMS current rating
required by the input capacitor.
Use a mix of input bypass capacitors to control the voltage
overshoot across the MOSFETs. Use ceramic capacitance for
the high frequency decoupling and bulk capacitors to supply
the RMS current. Small ceramic capacitors should be placed
very close to the drain of the upper MOSFET to suppress the
voltage induced in the parasitic circuit impedances.
For bulk capacitance, several electrolytic capacitors
(Panasonic HFQ series or Nichicon PL series or Sanyo
MV-GX or equivalent) may be needed. For surface mount
designs, solid tantalum capacitors can be used, but caution
must be exercised with regard to the capacitor surge current
rating. These capacitors must be capable of handling the
surge-current at power-up. The TPS series available from
AVX, and the 593D series from Sprague are both surge
current tested.
MOSFET Selection and Considerations
In high-current PWM applications, the MOSFET power
dissipation, package selection and heatsink are the
dominant design factors. The power dissipation includes two
loss components; conduction loss and switching loss. These
losses are distributed between the upper and lower
MOSFETs according to duty factor (see Equation 9). The
conduction losses are the main component of power
dissipation for the lower MOSFETs, Q
Only the upper MOSFETs, Q
switching losses, since the lower device turns on and off into
near zero voltage.
The equations assume linear voltage-current transitions and
do not model power loss due to the reverse-recovery of the
lower MOSFETs body diode. The gate-charge losses are
dissipated by the Driver IC and don't heat the MOSFETs.
0.5
0.4
0.3
0.2
0.1
FIGURE 15. CURRENT MULTIPLIER vs DUTY CYCLE
0
0
4 CHANNEL
0.1
DUTY CYCLE (V
0.2
1
and Q
3 CHANNEL
SINGLE
CHANNEL
0.3
3
O
2
/V
have significant
and Q
IN
2 CHANNEL
)
4
0.4
of Figure 1.
May 5, 2008
FN9034.3
0.5