HIP6004 datasheet(6/12 Pages) INTERSIL

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referenced to VIN) exceeds the voltage across ROCSET, the

over-current function initiates a soft-start sequence. The soft-

start function discharges CSS with a 10µA current sink and

inhibits PWM operation. The soft-start function recharges CSS,

and PWM operation resumes with the error amplifier clamped

to the SS voltage. Should an overload occur while recharging

CSS, the soft start function inhibits PWM operation while fully

charging CSS to 4V to complete its cycle. Figure 4 shows this

operation with an overload condition. Note that the inductor

current increases to over 15A during the CSS charging interval

and causes an over-current trip. The converter dissipates very

little power with this method. The measured input power for the

conditions of Figure 4 is 2.5W.

The over-current function will trip at a peak inductor current

(IPEAK) determined by:

where IOCSET is the internal OCSET current source (200µA

typical). The OC trip point varies mainly due to the MOSFETs

rDS(ON) variations. To avoid over-current tripping in the

normal operating load range, find the ROCSET resistor from

the equation above with:

1. The maximum rDS(ON) at the highest junction temperature.

2. The minimum IOCSET from the speciﬁcation table.

3. Determine IPEAK for

where

∆I is the output inductor ripple current.

For an equation for the ripple current see the section under

component guidelines titled ‘Output Inductor Selection’.

A small ceramic capacitor should be placed in parallel with

ROCSET to smooth the voltage across ROCSET in the

presence of switching noise on the input voltage.

Output Voltage Program

The output voltage of a HIP6004 converter is programmed

to discrete levels between 1.3VDC and 3.5VDC. The

voltage identification (VID) pins program an internal voltage

reference (DACOUT) with a 5-bit digital-to-analog converter

(DAC). The level of DACOUT also sets the PGOOD and

OVP thresholds. Table 1 specifies the DACOUT voltage for

the 32 combinations of open or short connections on the

VID pins. The output voltage should not be adjusted while

the converter is delivering power. Remove input power

before changing the output voltage. Adjusting the output

voltage during operation could toggle the PGOOD signal

and exercise the overvoltage protection.

The DAC function is a precision non-inverting summation

ampliﬁer shown in Figure 5. The resistor values shown are

only approximations of the actual precision values used.

Grounding any combination of the VID pins increases the

DACOUT voltage. The ‘open’ circuit voltage on the VID pins

is the band gap reference voltage, 1.26V.

PEAK

OCSET

•

DS ON

()

---------------------------------------------------

PEAK

OUT MAX

()

∆I

() 2

⁄

TABLE 1. OUTPUT VOLTAGE PROGRAM

PIN NAME

NOMINAL

OUTPUT

VOLTAGE

DACOUT

PIN NAME

NOMINAL

OUTPUT

VOLTAGE

DACOUT

VID4

VID3

VID2

VID1

VID0

VID4

VID3

VID2

VID1

VID0

01111

1.30

11111

2.0

01110

1.35

11110

2.1

01101

1.40

11101

2.2

01100

1.45

11100

2.3

01011

1.50

11011

2.4

01010

1.55

11010

2.5

01001

1.60

11001

2.6

01000

1.65

11000

2.7

00111

1.70

10111

2.8

00110

1.75

10110

2.9

00101

1.80

10101

3.0

00100

1.85

10100

3.1

00011

1.90

10011

3.2

00010

1.95

10010

3.3

00001

2.00

10001

3.4

00000

2.05

10000

3.5

NOTE: 0 = connected to GND or VSS, 1 = OPEN.

HIP6004

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