Diodes ZXGD3101N8 User Manual

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SYNCHRONOUS RECTIFIER CONTROLLER

Description

The ZXGD3101 is intended to drive MOSFETS configured as ideal diode replacements. The device is comprised of a differential amplifier detector stage and high current driver. The detector monitors the reverse voltage of the MOSFET such that if body diode conduction occurs a positive voltage is applied to the MOSFET’s Gate pin.

Once the positive voltage is applied to the Gate the MOSFET switches on allowing reverse current flow. The detectors’ output voltage is then proportional to the MOSFET Drain-Source reverse voltage drop and this is applied to the Gate via the driver. This action provides a rapid turn off as current decays.

Application

• Flyback Converters in:

• Adaptors

• LCD Monitors

• Server PSU’s

• Set Top Boxes

• LLC Converter in:

• High Power Adaptors

• LCD TV

• Street Lighting

Refer to documents: AN54, AN69, DN90, DN91 and DN94 available from the website

Features

• Turn-off propagation delay 15ns and turn-off time 20ns.

• Suitable for Discontinuous Mode (DCM), Critical

Conduction Mode (CrCM) and Continuous Mode (CCM) operation

• Compliant with Energy Star V2.0 and European Code of Conduct V3

• Halogen Free part

• 5-15V Vcc range

Mechanical Data

• Case: SO-8

• Marking Information: See Page 13

Diodes Incorporated

ZXGD3101N8

Ordering Information

Product Status Package Marking Reel size (inches) Tape width (mm) Quantity per reel

ZXGD3101N8TC Active SO-8 ZXGD3101 13 12 2500

ZXGD3101N8

Document Number DS31945 Rev. 1 - 2

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ZXGD3101N8

Maximum Ratings

Parameter Symbol Limit Unit

V

Supply voltage (Note 1)

Continuous Drain pin voltage (Note 1)

GATEH and GATEL output Voltage (Note 1)

Driver peak source current

Driver peak sink current

Reference current

CC

V

D

V

G

I

SOURCE

I

SINK

I

REF

15 V

-3 to180 V

-3 to V

+ 3 V

CC

4 A

7 A

25 mA

V

Bias voltage

Bias current

Power dissipation at TA =25°C

Operating junction temperature

Storage temperature

BIAS

I

BIAS

P

T

STG

D

J

-40 to +150 °C

-50 to +150 °C

V

CC

100 mA

490 mW

Thermal Characteristics

Parameter Symbol Value Unit

Junction to ambient (Note 2)

Junction to lead (Note 3)

R

JA

R

lA

255 °C/W

120 °C/W

ESD Rating

Model Rating Unit

Human Body 4000 V

Machine 400 V

Notes: 1.All voltages are relative to GND pin

2. Mounted on minimum 1oz weight copper on FR4 PCB in still air conditions.

3. Output Drivers - Junction to solder point at end of the lead 5 and 6

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ZXGD3101N8

Electrical Characteristics @T

Parameter Symbol Conditions Min. Typ. Max. Unit

Input and supply characteristics

Operating current

Gate Driver

Turn-off Threshold Voltage(Note 4)

GATE output voltage (Note 4)

GATEH peak source current

= 25°C, VCC= 10V,

A

I

OP

V

T

V

G(off)

VG

I

V

SOURCE

=1.8k, R

RBIAS

 -200m V

V

DRAIN

V

 0V

DRAIN

= 1V, (Note 5)

G

 0V, (Note 5)

V

DRAIN

V

= -60mV, (Note 6)

DRAIN

V

= -80mV, (Note 6)

DRAIN

V

= -100mV, (Note 6)

DRAIN

V

 -140mV, (Note 6)

DRAIN

V

 -200mV, (Note 6)

DRAIN

= 1V

GH

REF

=3k

- 3 mA

- 8 -

-45 -16 0 mV

- 0.6 1

5.0 7.5 -

7.0 8.5 V

8.4 9 -

9.2 9.4 -

9.3 9.5 -

2.5 - A

GATEL peak sink current

Turn on Propagation delay Turn off Propagation delay Gate rise time Gate fall time

Notes: 4. GATEH connected to GATEL

= 100k, RL = O/C

5. R

H

= 100k, RH = O/C

6. R

L

7. Refer to Fig 6: test circuit and Fig 7: timing diagram on Page 12

V

SINK

t

d1

t

d2

t

r

t

f

= 5V

GL

C

= 2.2nF, (Notes 6 and 7)

L

2.5 - A

525 ns 15 ns 305 ns 20 ns

I

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Schematic Symbol and Pin Out Details

+

Differential amplifier

-

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ZXGD3101N8

SYNCHRONOUS RECTIFIER CONTROLLER

Vcc

Gate drive

amplitude

control

DRAIN

+

High volt

-

comparator

Turn-on/off

control

Threshold

voltage control

REF BIAS

GATEH

Driver

GATEL

GND

Pin No. Symbol Description and function

1 NC

2 REF

3 GATEL

4 GATEH

5

V

CC

6 GND

7 BIAS

8 DRAIN

Notes: 8. REF pin should be assumed to be at GND +0.7V.

9. BIAS pin should be assumed to be at GND +0.3V.

ZXGD3101N8

Document Number DS31945 Rev. 1 - 2

No connection

This pin can be connected to GND

Reference

This pin is connected to V

via resistor, R

CC

REF

. R

should be selected to source approximately 3mA into this pin.

REF

(Note 8)

Gate turn off

This pin sinks current, I

, from the synchronous MOSFET Gate.

SINK

Gate turn on

This pin sources current, I

Power Supply

This is the supply pin. It is recommended to decouple this point to ground closely with a ceramic capacitor.

, to the synchronous MOSFET Gate.

SOURCE

Ground

This is the ground reference point. Connect to the synchronous MOSFET Source terminal.

Bias

This pin is connected to V

via resistor, R

CC

BIAS

. R

should be selected to source 1.6 times I

BIAS

(Note 9)

Drain connection

This pin connects directly to the synchronous MOSFET Drain terminal.

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into this pin.

REF

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SYNCHRONOUS RECTIFIER CONTROLLER

Operation

Normal Operation

The operation of the device is described step-by-step with reference to the timing diagram below.

1. The detector monitors the MOSFET Drain-Source voltage.

2. When, due to transformer action, the MOSFET body diode is forced to conduct there is approximately -0.6V on the Drain pin.

3. The detector outputs a positive voltage with respect to ground, this voltage is then fed to the MOSFET driver stage and current is sourced out of the GATEH pin.

4. The current out of the GATEH pin is sourced into the synchronous MOSFET Gate to turn the device on.

5. The GATEH output voltage is now proportional to the Drain-Source voltage drop across the MOSFET due to the current flowing through the MOSFET.

6. MOSFET conduction continues until the drain current reaches zero.

7. At zero current the detector output voltage is zero and the synchronous MOSFET Gate voltage is pulled low by the GATEL, turning the device off.

Body Diode

Conduction

Drain

current

zero

MOSFET Gate Current

ZXGD3101N8

Document Number DS31945 Rev. 1 - 2

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