Richtek RT8463GCP, RT8463GQW Schematic [ru]

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RT8463

High Voltage Multi-Topology LED Driver

General Description

The RT8463 is a current mode PWM regulator for LED driving applications. With a 2A power switch, wide input voltage (4.5V to 50V) and output voltage (up to 50V) ranges, the RT8463 can operate in any of the three common topologies : Buck, Boost or Buck-Boost.

With 470kHz operating frequency, the size of the external PWM inductor and input/output capacitors can be minimized. High efficiency is achieved by a 100mV current sensing control.

Brightness dimming can be controlled from either analog or PWM signal. A unique built-in clamping comparator and filtering resistor allow easy low noise analog dimming conversion from PWM signal with only one external capacitor.

The RT8463 is available in the TSSOP-14 (Exposed pad) and WDFN-12L 3x3 packages.

Features

zHigh Voltage : VIN Up to 50V, VOUT Up to 50V

zBuck, Boost or Buck-Boost Operation

zBuilt-In 2A Power Switch

zCurrent Mode PWM Control

z470kHz Fixed Switching Frequency

zEasy Dimming : Analog, PWM Digital or PWM Converting to Analog with One External Capacitor

zAdjustable Soft-Start to Avoid Inrush Current

zAdjustable Over Voltage Protection to Limit Output Voltage

zThermal Shutdown

zUnder Voltage Lockout

zRoHS Compliant and Halogen Free

Applications

zGPS, Portable DVD Backlight

zDesk Lights and Room Lighting

zIndustrial Display Backlight

Ordering Information

RT8463

Package Type

CP : TSSOP-14 (Exposed Pad)

QW : WDFN-12L 3x3 (W-Type)

Lead Plating System

G : Green (Halogen Free and Pb Free)

Note :

Richtek products are :

`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.

`Suitable for use in SnPb or Pb-free soldering processes.

Marking Information

RT8463GCP

RT8463GCP : Product Number

RT8463 YMDNN : Date Code

GCPYMDNN

RT8463GQW

98 = : Product Code

98=YM YMDNN : Date Code

DNN

Simplified Application Circuit

L

D1

VIN

VOUT

 

 

C1

RT8463

 

C6

 

 

 

 

 

 

 

 

VCC

SW

R2

 

5V

 

 

EN

ISP

 

 

 

 

 

PWM

 

 

DCTL

ISN

R3

 

Dimming Control

 

 

VC

OVP

VOUT

 

 

 

 

 

 

 

 

 

 

 

 

 

R1

C3

 

SS

CREG

R4

 

 

C4

ACTL

GND

C5

 

C2

 

 

 

 

Copyright ©2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8463-00 January 2013

www.richtek.com

 

1

RT8463

Pin Configurations

(TOP VIEW)

ISP

 

 

14

VCC

ISN

2

 

13

CREG

VC

3

 

12

SW

ACTL

4

GND

11

GND

DCTL

5

 

10

SS

EN

6

15

9

OVP

GND

7

 

8

GND

TSSOP-14 (Exposed Pad)

ISP 1

 

12

VCC

ISN 2

 

11

CREG

VC 3

GND

10

SW

ACTL 4

9

GND

 

DCTL 5

 

8

SS

EN 6

13 7

OVP

WDFN-12L 3x3

Functional Pin Description

Pin No.

 

 

 

TSSOP-14

WDFN-12L 3x3

Pin Name

Pin Function

 

(Exposed Pad)

 

 

 

1

1

ISP

Positive Current Sense Input.

 

 

 

 

 

2

2

ISN

Negative Current Sense Input. Voltage threshold between ISP and

ISN is 100mV.

 

 

 

 

 

3

3

VC

Compensation Node for PWM Boost Converter Loop.

 

 

 

 

 

4

4

ACTL

Analog Dimming Control Input. Effective programming range is

between 0.2V and 1.2V.

 

 

 

 

 

 

 

 

Digital Dimming Control Input. By adding a 0.47μF filtering

5

5

DCTL

capacitor on the ACTL pin, the PWM dimming signal on DCTL pin

will be averaged and converted into analog dimming signal on the

 

 

 

 

 

 

ACTL pin. VACTL = 1.2V x PWM dimming duty cycle.

 

6

6

EN

Enable Control Input (Active High). When this pin is low, the chip is

in shutdown mode.

 

 

 

 

 

7, 8, 11, 15

9,

GND

Ground. The exposed pad must be soldered to a large PCB and

(Exposed Pad)

13 (Exposed Pad)

connected to GND for maximum power dissipation.

 

9

7

OVP

Over Voltage Protection Sense Input. The PWM Boost converter

turns off when VOVP goes higher than 1.2V.

 

 

 

 

 

10

8

SS

Soft-Start Time Setting. A minimum 10nF capacitor is required for

soft-start.

 

 

 

 

 

12

10

SW

Switch Node of PWM Boost Converter.

 

 

 

 

 

 

13

11

CREG

Regulator Output for Internal Circuit. Placed a 1μF

capacitor to

stabilize the 5V output regulator.

 

 

 

 

 

14

12

VCC

Power Supply Voltage Input. For good bypass,

a low ESR

capacitor is required.

 

 

 

 

 

Copyright ©2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8463-00 January 2013

2

RT8463

Function Block Diagram

VCC

-

OSC

 

4.5V

+

 

OVP

+

 

1.2V

-

 

EN

+

Shutdown

1.4V

-

 

VC

 

 

 

 

5µA

SS

 

 

 

1.2V

 

DCTL

+

 

-

SW

 

5V

CREG

S

LDO

 

 

 

R

 

 

R

 

 

+ -

GM-

ISN

+

ISP

+

-

GND

 

 

ACTL

 

VISP – VISN

 

 

 

(mV)

 

 

 

100

 

 

 

0

0.2

1.2

VACTL (V)

 

 

Figure 1

Operation

The RT8463 is specifically designed to be operated in Buck, Boost and Buck-Boost converter applications. This device uses a fixed frequency, current mode control scheme to provide excellent line and load regulations. The control loop has a current sense amplifier to sense the voltage between the ISP and ISN pins and provides an output voltage at the VC pin. A PWM comparator then turns off the internal power switch when the sensed power switch current exceeds the compensated VC pin voltage. The power switch will not reset by the oscillator clock in each cycle. If the comparator does not turn off the switch in a cycle, the power switch is on for more than a full

switching period until the comparator is tripped. In this manner, the programmed voltage across the sense resistor is regulated by the control loop.

The current through the sense resistor is set by the programmed voltage and the sense resistance. The voltage across the sense resistor can be programmed by either the analog or PWM signals at the ACTL pin, or the PWM signal at the DCTL pin.

The RT8463 provides protection functions which include over temperature, input voltage under voltage, output voltage over voltage, and switch current limit.

Copyright ©2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8463-00 January 2013

www.richtek.com

 

3

RT8463

Absolute Maximum Ratings (Note 1)

z Supply Input Voltage, VCC ------------------------------------------------------------------------------------

−0.3V to 60V

z SW Pin Voltage at Switching Off, ISP, ISN ----------------------------------------------------------------

−0.3V to 60V

z DCTL, ACTL, CREG, OVP Pin Voltage --------------------------------------------------------------------

−0.3V to 5.5V (Note 2)

z EN Pin Voltage ---------------------------------------------------------------------------------------------------

−0.3V to 20V

z Power Dissipation, PD @ TA = 25°C

 

TSSOP-14 (Exposed Pad) ------------------------------------------------------------------------------------

3.32W

WDFN-12L 3x3 ---------------------------------------------------------------------------------------------------

3.28W

z Package Thermal Resistance (Note 3)

 

TSSOP-14 (Exposed Pad), θJA ------------------------------------------------------------------------------

30.1°C/W

TSSOP-14 (Exposed Pad), θJC ------------------------------------------------------------------------------

7.5°C/W

WDFN-12L 3x3, θJA ---------------------------------------------------------------------------------------------

30.5°C/W

WDFN-12L 3x3, θJC ---------------------------------------------------------------------------------------------

7.5°C/W

z Junction Temperature -------------------------------------------------------------------------------------------

150°C

z Lead Temperature (Soldering, 10 sec.) ---------------------------------------------------------------------

260°C

z Storage Temperature Range ----------------------------------------------------------------------------------

−65°C to 150°C

z ESD Susceptibility (Note 4)

 

HBM (Human Body Model) ------------------------------------------------------------------------------------

2kV

MM (Machine Model) -------------------------------------------------------------------------------------------

200V

Recommended Operating Conditions

(Note 5)

z Supply Input Voltage, VCC ------------------------------------------------------------------------------------

4.5V to 50V

z Junction Temperature Range ----------------------------------------------------------------------------------

−40°C to 125°C

z Ambient Temperature Range ----------------------------------------------------------------------------------

−40°C to 85°C

Electrical Characteristics

(VCC = 12V, No Load on any Output, TA = 25°C, unless otherwise specified)

Parameter

Symbol

 

Test Conditions

Min

Typ

Max

Unit

 

 

 

 

 

 

 

 

 

Overall

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Regulator Output Voltage

VCREG

 

ICREG = 20mA

4.5

5

5.5

V

Supply Current

IVCC

 

VC ≤ 0.2V (Not Switching )

--

--

5

mA

VIN Under Voltage Lockout

VUVLO

 

VIN Rising

--

4.2

--

V

Threshold

 

VIN Falling

--

3.8

--

 

 

 

Shutdown Current

ISHDN

 

VEN < 0.5V

--

--

15

μA

EN Input Voltage

Logic-High

VEN_H

 

 

2

--

--

V

Logic-Low

VEN_L

 

 

--

--

0.5

 

 

 

 

EN Input Current

 

 

VEN > 2V

--

--

1

μA

Current Sense Amplifier

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Input Threshold (VISP − VISN)

 

 

VACTL ≥ 1.25V

96

100

102

mV

 

 

 

 

 

 

 

 

VACTL = 1.2V

95

98

101

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

 

 

 

 

DS8463-00 January 2013

4

RT8463

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Input Current

 

IISP

VISP = 24V

--

200

--

μA

Input Current

 

IISN

VISN = 24V

--

20

--

μA

Output Current

 

IVC

2V > VC > 0.2V

--

±10

--

μA

VC Threshold for PWM Switch Off

 

 

--

0.2

--

V

 

 

 

 

 

 

 

 

 

LED Dimming

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analog Dimming ACTL Pin Input

IACTL

0 ≤ VACTL ≤ 3V, DCTL Floating

--

--

2

μA

Current

 

 

 

 

 

 

 

 

LED Current On Threshold at

VACTL_ON

(VISP − VISN) = 100mV

--

1.2

1.33

V

ACTL

 

 

 

 

 

 

 

 

LED Current Off Threshold at

VACTL_OFF

 

--

0.2

0.25

V

ACTL

 

 

 

 

 

 

 

 

 

DCTL Input Current

 

IDCTL

0.3V ≤ VDCTL ≤ 5V

--

0.5

2

μA

DCTL Input

 

Logic-High

VDCTL_H

 

2

--

--

V

Voltage

 

Logic-Low

VDCTL_L

 

--

--

0.1

 

 

 

 

 

 

 

PWM Boost Converter

 

 

 

 

 

 

Switching Frequency

fSW

 

420

470

520

kHz

Maximum Duty Cycle

DMAX

 

--

--

100

%

 

 

 

 

 

 

 

 

Minimum On-Time

(Note 6)

 

 

--

150

250

ns

 

 

 

 

 

 

 

 

SW RDS(ON)

 

 

 

--

0.3

0.5

Ω

SW Current Limit

 

ILIM_SW

 

2

2.5

--

A

OVP and Soft-Start

 

 

 

 

 

 

 

OVP Threshold

 

VOVP

 

1.15

1.2

1.25

V

OVP Input Current

 

IOVP

VOVP ≤ 1.5V

--

--

50

nA

Soft-Start SS Pin Current

ISS

VSS ≤ 2.5V

--

5

8

μA

Temperature Protection

 

 

 

 

 

 

Thermal Shutdown Temperature

TSD

 

--

150

--

°C

Thermal Shutdown Hysteresis

TSD

 

--

20

--

°C

Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability.

Note 2. If connected with a 20kΩ serial resistor, ACTL and DCTL can go up to 40V.

Note 3. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package.

Note 4. Devices are ESD sensitive. Handling precaution is recommended.

Note 5. The device is not guaranteed to function outside its operating conditions. Note 6. Guaranteed by design, not subjected to production test.

Copyright ©2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8463-00 January 2013

www.richtek.com

 

5

Richtek RT8463GCP, RT8463GQW Schematic

RT8463

Typical Application Circuit

VIN

 

 

 

 

D1

 

4.5V to 50V

 

C1

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8463

R2

 

 

 

 

VCC

ISP

100mV

 

 

 

 

 

 

5V

 

EN

ISN

 

R3

R4

PWM

 

DCTL

OVP

 

 

 

 

 

 

 

 

Dimming control

 

 

GND

 

 

C6

 

 

VC

 

 

 

 

CREG

 

 

R1

 

C5

 

 

 

 

 

 

 

 

SS

 

1µF

L

 

10k

 

 

 

 

C3

ACTL

SW

 

22µH

 

C2

 

 

 

10nF

 

 

 

 

3.3nF

 

C4

 

 

 

 

 

 

0.47µF

 

 

 

 

Figure 2. PWM to Analog Dimming Buck Configuration

VIN

 

 

 

 

D1

 

4.5V to 50V

C1

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8463

 

R2

 

 

 

VCC

 

ISP

100mV

 

Analog

 

 

 

 

ACTL

 

ISN

 

R3

R4

Dimming

 

 

DCTL

OVP

 

 

 

 

 

 

 

 

 

 

 

 

5V

EN

 

GND

 

 

C6

CREG

 

 

 

VC

C5

 

 

 

 

 

 

 

R1

SS

 

 

1µF

L

 

10k

 

SW

 

15µH

 

C2

C3

 

 

 

 

 

 

 

 

 

10nF

 

 

 

 

 

3.3nF

 

 

 

 

 

 

Figure 3. Analog Dimming Buck Configuration

VIN

 

 

 

 

D1

 

 

 

 

 

 

 

4.5V to 50V

C1

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8463

 

R2

 

 

 

VCC

 

ISP

100mV

 

 

 

 

 

 

PWM

ACTL

 

ISN

 

R3

R4

Dimming control

 

OVP

 

 

 

 

DCTL

 

 

 

 

 

 

 

 

5V

EN

 

GND

 

 

C6

CREG

 

 

 

VC

C5

 

 

 

 

 

 

 

R1

SS

 

 

1µF

L

 

10k

 

 

 

15µH

 

C3

 

SW

 

 

C2

 

 

 

 

10nF

 

 

 

 

 

3.3nF

 

 

 

 

 

 

Figure 4. PWM Dimming Buck Configuration Through ACTL Pin

Copyright ©2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8463-00 January 2013

6

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