IR3507PbF

Page 11 of 19

IR Confidential

April 2, 2009

NOT RECOMMENDED FOR NEW DESIGNS

REPLACEMENT PRODUCT – IR3507ZPBF

share loop is much slower than that of the voltage loop and the two loops do not interact. For proper current sharing the

output of current sense amplifier should note exceed (VCCL-1.4V) under all operating condition.

IR3507 THEORY OF OPERATION

Block Diagram

The Block diagram of the IR3507 is shown in Figure 5, and specific features are discussed in the following sections.

500K

ANTI-BIAS

LATCH

+

-

200mV

PSI

550mV

620mV

1V

PSI

COMPARATOR

PSI ASSERT

CLK

D

Q

NEGATIVE

CURRENT

LATCH

RESET

DOMINANT

+

S

R

Q

PWMQ

VCCL

EAIN

CLK

D

Q

Q

3K

+

-

S

R

Q

+

-

+

-

CLK

D

Q

+

-

+

-

+

-

EAIN

+

-

S

R

Q

VCC

LGND

IOUT

EAIN

VCCL

CSIN-

GATEL

PGND

BOOST

CLKIN

DACIN

PHSOUT

SW

GATEH

CSIN+

PHSIN

VCC

CALIBRATION

RMPOUT

DACIN

CALIBRATION

CSAOUT

PWM RESET

SHARE_ADJ

PHSIN

DACIN

CALIBRATION

VCCL

IROSC

IROSC

DEBUG OFF

PWM COMPARATOR

PWM LATCH

SHARE

ADJUST

AMPLIFIER

DACIN-SHARE_ADJ

-

1V

X32.5

CURRENT SENSE

AMPLIFIER

BODY BRAKING

COMPARATOR

1V

SYNCHRONOUS RECTIFICATION

DISABLE COMPARATOR

+

PWM RAMP

GENERATOR

OVP

COMPARATOR

GATEL NON-

OVERLAP

COMPARATOR

+

GATEL NON-

OVERLAP

LATCH

GATEH NON-

OVERLAP

LATCH

GATEL

DRIVER

GATEH

DRIVER

X

0.75

DEBUG

COMPARATOR

SET

DOMINANT

SET

DOMINANT

NEGATIVE CURRENT

COMPARATOR

0.8V

(LOW=OPEN)

RESET

DOMINANT

0.15V

GATEH NON-

OVERLAP

COMPARATOR

200mV

100mV

CLK

D

Q

PHSIN

VCCL

8CLK

VCCL

CLK

D

Q

PWM_CLK

.

.

.

Q_100%DUTY

(CLKIN IF 1-PHASE)

+

-

RMPOUT

100% DUTY

LATCH

PWMQ

Q_100%DUTY

PWM_CLK

CLK

D

Q

Figure 5: Block diagram

Tri-State Gate Drivers

The gate drivers can deliver up to 2A peak current (4A sink current for bottom driver). An adaptive non-overlap

circuit monitors the voltage on the GATEH and GATEL pins to prevent MOSFET shoot-through current while

minimizing body diode conduction. The non-overlap latch is added to eliminate the error triggering caused by the

switching noise. An enable signal is provided by the control IC to the phase IC without the addition of a dedicated

signal line. The error amplifier output of the control IC drives low in response to any fault condition such as VCCL

under voltage or output overload. The IR3507 Body Braking

output low. This tri-state operation prevents negative inductor current and negative output voltage during power-

down.