The IR3220S is a fully protected dual high side switch I.C that
integrates an H�bridge motor controller with two very efficient
high side MOSFETs in a single 20-pin package. The IR3220S
combines with the two low side IRF7484Q MOSFETs as few as
10 external passive components to provide a complete, fully op-
erational and fully protected H-bridge control actuator with for-
ward, reverse, braking and non-braking modes without the need
of a micro-controller.

Functional Description

The high side switches provide the direction capability and the H-
bridge protection. The low side MOSFETs bring the flexibility by
offering the high frequency switching ability. Therefore, crude
start-up of the motor is avoided and replaced by a smooth and
stress-less speed ramp-up.

The IR3220S features shoot-through protection for each leg, H-
bridge logic control, soft-start sequence and over-current / over-
temperature shutdown protections. Two input signals (IN1 & IN2)
select the operating modes while the PWM soft-start sequence
cycles the corresponding active low side MOSFET in order to
limit the motor in-rush current. The soft-start sequence is pro-
grammed by an RC time constant and reset itself automatically.
Thanks to the inner PWM oscillator, the IR3220S can also be
the final stage of an overall torque or speed loop. If needed, an
external clock may force the H-bridge switching operation. This
can be combined with low frequency PWM operation through
the IN1(2) inputs.

The IR3220S is a Co-pack IPS product offering very low Rds(on)
and a high level of functionality and protection. Its open architec-
ture and programmability helps the designer to optimize each
motor drive upon the application requirements at a very low cost.
For automotive actuators, the motor is kept shorted even during
the low consumption sleep mode. Shoot-through protection, over-
temperature & over-current shutdowns, self-adaptive dead-time
and PWM circuitries are described in details in the

AN 1032

Application Note. A general purpose method to help rating the
soft-start sequence as well as layout and thermal considerations
are also covered. Finally, a 6A DC motor actuator with a PCB
size down to 1 Inch� is suggested in the document.

IR3220S

Data Sheet No.PD60180-C

FULLY PROTECTED H-BRIDGE FOR D.C. MOTOR

Features

8-Lead SOIC

IRF7484Q

Packages

20-Lead SOIC

(wide body)

www.irf.com

Programmable PWM In-rush
Current Limitation (e.g 18A)

6 A Continuous Current Capability

without Heat Sink (2 x 13 m

)

Over-Temperature (165 �C) and
Over-Current (30A) Protections

20 kHz PWM Oscillator Embedded

Low & High Frequency Switching
Operation (self adaptive dead-time)

Easy Speed / Torque Control
(analog duty cycle input)

Braking / Non-Braking Modes

Sleep Mode (braking) for
Automotive Actuator

IR3220S

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Functional Block Diagram

(see AN-1032 for a detailed description of each block)

H Bridge logic control
& status feedback

VCC

IN 1

IN 2

Shoot-through
protection

M 2

G 1

M 1

M 2

G 2

Oscillator

Gnd

+

-

Soft Start duty cycle

S S reset

Over current
shutdown

Over temp.
protection

Vrc

5.5 V Ref.

10 mA

Over current
shutdown

Shoot-through
protection

Low Side
Driver

40 V Active Clamp

0.5k

Thanks to the self-adaptive dead-time circuitry, the low side MOSFET of each leg is driven in the opposite
phase of the high side one without any conflict. Thus, the single IN1 signal turns on the leg M1 (and IN2, the
output M2). Consequently, when both IN1 and IN2 are low, the quiescent state of the H-bridge is the Braking
Mode (the two low side MOSFETs on). The over-temperature circuitry and the two over-current protections
(one per leg) protect the IC and flag the DG pin. The thermal shutdown also covers the body diode over-
heating. Fault conditions are reset by cycling the corresponding IN1(2) input. Each leg appears independent
so that the PWM soft-start management is greatly simplified and makes the 20kHz oscillator block almost a
separate function. The positive input of the PWM comparator is accessible on the SS pin. An external analog
voltage or a RC network can either drive the duty cycle. It has to be said that a clock signal (< 20 kHz) applied
on this input will directly drive the low side MOSFETs. A 5V voltage source is embedded in the I.C ( switched
off while in the sleep mode ) so that no additional power supply is needed for the soft-start RC time constant.
Its capacitor is discharged through the `' SS reset `' circuitry every time IN1 equals IN2. Thus, the soft-start
sequence is ready to operate whichever the formerly braking mode was.

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Soft-Start Sequence

t

t

t

IN1

(IN2)

SS

M1-M2

(M2-M1)

Duty cycle modulation follows SS voltage

Tss ( approximately 1.4 x RC time constant )

Trd

Vss+

Vss-

Truth Table

IN1 IN2

MODES

HS1 LSS1

HS2 LSS2 SS reset

Stand-by with braking - sleep mode**

OFF

Forward rotation (normal operation)

OFF

ON*

OFF

Forward rotation (protection triggered)

OFF

ON*

OFF

Reverse rotation (normal operation)

OFF

ON*

OFF

Reverse rotation (protection triggered)

OFF

ON*

OFF

Stand-by without braking

OFF

* During Soft-start sequence, the low side part is switching.

** Protections are reset in this mode

The IR 3220S over-current is set at 30A which is low enough to protect the whole application. The soft-start RC
time constant has to be designed in order to keep the maximum in-rush current below the I shutdown (application
worst case - see AN 1032 ). The total switching sequence is about 1.4 times the RC time constant. A smoother
start-up is even achievable by slightly increasing the RC values. However, the soft-start sequence should
remain short enough not to trip the over-temperature protection (Tj while free-wheeling). The truth table shows
that the soft-start sequence can be interrupted at any time. But a minimum time is needed prior to any change
in the direction or re-start of a new SS sequence. Actually, the capacitor of the RC network has to be discharged
and the motor fully stopped first otherwise the over-current protection might trip during the next turn-on.

The protections turn off the high side MOSFETs so that no braking sequence follows the fault detection. Both
IN1 and IN2 have to go low for a minimum time in order to reset the fault circuitry. When both inputs are back
to the low level, the H-bridge is in the braking mode and the motor shorted. In this mode, no protection is
activated and the peak current due to the braking is not monitored. After 300 ms, the I.C sleep mode is
activated and the consumption is reduced down to few micro-amps. The low side gate drivers keep the gates
high so the motor remains shorted. When using end switches, the I.C goes into the low consumption mode as
soon as the mechanical stop are reached. When interfacing such switches directly to the IR 3220S, de-bounc-
ing RC networks have to be implemented on the input pins in order to prevent false over-current detection.

IR3220S

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The PWM generator is based on a 3V saw-tooth oscillator. The soft-start sequence takes advantage of the RC
charge profile in order to perform a smooth duty cycle variation. When the SS pin is below 1.2V, no PWM signal
is sent to the low side MOSFETs. When it exceeds 4.2V, they are permanently ON. By designing the proper RC
network, the start-up can either be very slow without any in-rush current or, fast and efficient by shortening the
PWM sequence. In addition to the quiescent braking mode, the IR 3220S is able to open the four MOSFETs
simultaneously if the mechanical load requires its natural slow-down (stand-by mode without braking). The
four modes and their corresponding DC motor current profiles are summarized in the Timing Diagram.

Over-load protection is achieved thanks to the I.C temperature shutdown protection. By using the recom-
mended part number and the proper cooling, the whole H-bridge is protected by the IR 3220S's inner over-
temperature circuitry (see AN 1032). A micro-controller is able to directly drive the PWM duty cycle by forcing
a 0 to 5V voltage on the SS pin (e.g. through a 10K resistor). Thus, closing a speed or torque control loop for
advanced applications becomes very easy. Since the low side MOSFETs are the only ones switching, the
IR 3220S body diodes offer the freewheeling path to the motor. The power dissipated in each body diode while
switching may appear high enough to trip the over-temperature protection. For permanent switching operation,
external Schottky diodes should be implemented between each output (M1 & M2) and the VCC pin.

Permanent Switching Operation

(without external RC time constant)

Copper plates added to the footprints will improve the cooling.
However, the low side MOSFETs should always remain colder
and thermally independent from the IR 3220S. The power path
has to be designed carefully and shall include both a decoupling
capacitor (e.g. 100 nF ceramic) and a reservoir capacitor (e.g.
Cres ( uF). = I pk soft-start (A) x 25). The window-lifter is a
good example where the IR 3220S's PWM ability greatly en-
hances the application. The current is monitored thanks to a
shunt and sent back to the micro-controller which takes over
the torque control loop (anti-pinch function).

Micro
Controller

Speed

Direction &
Braking

Diagnostic

+5V

+Bat

-Bat

IR 3220

In1

In2

DC Motor

Over-voltage
protection

Additional
Schottky diodes

Additional Schottky diodes
have to be implemented if
the I.C temperature appears
too high.

A over-voltage protection
may be needed depending
on the power supply wire
length

Star Connection

Gnd

Vcc

IRF 7484

Электронный компонент: IR3220STR