2-116

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 together as possible.

numerous physical capacitors. Locate the HIP6005B within 3

MOSFET’s gate and source connections from the HIP6005B

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)

The modulator transfer function is the small-signal transfer

peak-to-peak oscillator voltage

Modulator Break Frequency Equations

The compensation network consists of the error amplifier

closed loop transfer function with the highest 0dB crossing

degrees

. The equations below relate the compensation

locating the poles and zeros of the compensation network:

6. Check Gain against Error Amplifier’s Open-Loop Gain.

7. Estimate Phase Margin - Repeat if Necessary.

UGATE

PHASE

RETURN

HIP6005B

FIGURE 5. PRINTED CIRCUIT BOARD POWER AND GROUND

PLANES OR ISLANDS

HIP6005B

SS

GND

BOOT

PHASE

FIGURE 6. PRINTED CIRCUIT BOARD SMALL SIGNAL

LAYOUT GUIDELINES

+12V

OSC

REFERENCE

ESR

OSC

ERROR

AMP

PWM

DRIVER

(PARASITIC)

FIGURE 7. VOLTAGE-MODE BUCK CONVERTER

COMPENSATION DESIGN

DACOUT

COMP

FB

HIP6005B

COMPARATOR

DETAILED COMPENSATION COMPONENTS

+

-

+

-

+

-

PHASE

F

ESR

1

2

π x (ESR x C

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

=

F

LC

1

2

π xL

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

=

HIP6005B