7

Output Voltage Program

The output voltage of a HIP6015 converter is programmed to

identification (VID) pins program an internal voltage

reference (DACOUT) with a TTL-compatible 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 different combinations of

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.

All VID pin combinations resulting in a 0V output setting

activate the Power-On Reset function and disable the gate

drive circuitry. For these specific VID combinations, though,

PGOOD asserts a high level. This unusual behavior has

been implemented in order to allow for operation in dual-

microprocessor systems by AND-ing the PGOOD signals

from the two individual power converters.

Application Guidelines

Layout Considerations

As in any high frequency switching converter, layout is very

important. Switching current from one power device to

another can generate voltage transients across the

impedances of the interconnecting bond wires and circuit

traces. These interconnecting impedances should be

minimized by using wide, short printed circuit traces. The

critical components should be located as close together as

possible using ground plane construction or single point

grounding.

Figure 5 shows the critical power components of the

converter. To minimize the voltage overshoot the

interconnecting wires indicated by heavy lines should be

part of ground or power plane in a printed circuit board. The

components shown in Figure 6 should be located as close

circuit traces for the MOSFET’s gate and source connections

from the HIP6015 must be sized to handle up to 1A peak

current.

Figure 6 shows the circuit traces that require additional

layout consideration. Use single point and ground plane

construction for the circuits shown. Minimize any leakage

close to the SS pin because the internal current source is

only 10

to the BOOT and PHASE pins.

Feedback Compensation

Figure 7 highlights the voltage-mode control loop for a buck

Reference voltage level. The error amplifier (Error Amp)

triangular wave to provide a pulse-width modulated (PWM)

UGATE

PHASE

RETURN

HIP6015

FIGURE 5. PRINTED CIRCUIT BOARD POWER AND

GROUND PLANES OR ISLANDS

HIP6015

SS

GND

BOOT

PHASE

FIGURE 6. PRINTED CIRCUIT BOARD SMALL SIGNAL

LAYOUT GUIDELINES

+12V

HIP6015