Freescale Semiconductor 6 Channel LED Backlight Driver with Integrated Power Supply Evaluation Kit - MC34845 KIT34845EPE KIT34845EPEVME Datenbogen
Produktcode
KIT34845EPEVME
Document Number: MC34845
Rev. 6.0, 12/2011
Freescale Semiconductor
Advance Information
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2011. All rights reserved.
Low Cost 6 Channel LED
Backlight Driver with Integrated
Power Supply
Backlight Driver with Integrated
Power Supply
The 34845 series represents high efficiency LED drivers for use in
backlighting LCD displays from 10” to 17” +. Operating from supplies of
5.0 to 21V, the 34845 series is capable of driving up to 16 LEDs in series
in 6 separate strings. The LED current tolerance in the 6 strings is within
±2% maximum and is set using a resistor to GND.
5.0 to 21V, the 34845 series is capable of driving up to 16 LEDs in series
in 6 separate strings. The LED current tolerance in the 6 strings is within
±2% maximum and is set using a resistor to GND.
PWM dimming is performed by applying a PWM input signal to the
PWM pin which modulates the LED channels directly. An Enable Pin
(EN) provides for low power standby. Alternatively, a single wire
scheme selects power down when PWM is connected to the Wake Pin
and held low.
(EN) provides for low power standby. Alternatively, a single wire
scheme selects power down when PWM is connected to the Wake Pin
and held low.
The integrated boost converter uses dynamic headroom control to
automatically set the output voltage. There are three device versions for
boost frequency; 34845/C is 600 kHz, 34845A is 1.2 MHz and the
34845B/D is 300 kHz. External compensation allows the use of different
inductor/ capacitor combinations.
boost frequency; 34845/C is 600 kHz, 34845A is 1.2 MHz and the
34845B/D is 300 kHz. External compensation allows the use of different
inductor/ capacitor combinations.
The 34845 includes fault protection modes for LED short and open,
over temperature, over current and over voltage errors. It features an
internally fixed OVP value of 60V (typical) which protects the device in
the event of a failure in the externally programmed OVP. The OVP level
can be set by using an external resistor divider.
internally fixed OVP value of 60V (typical) which protects the device in
the event of a failure in the externally programmed OVP. The OVP level
can be set by using an external resistor divider.
Features
• Input voltage of 5.0 to 21V
• Boost output voltage up to 60V
• 2.0 A integrated boost FET
• Fixed boost frequency - 300 kHz, 600 kHz or 1.2 MHz
• OTP, OCP, UVLO fault detection
• LED short/open protection
• Programmable LED current between 3.0 mA and 30 mA
• 24-Ld 4x4x0.65mm
• Input voltage of 5.0 to 21V
• Boost output voltage up to 60V
• 2.0 A integrated boost FET
• Fixed boost frequency - 300 kHz, 600 kHz or 1.2 MHz
• OTP, OCP, UVLO fault detection
• LED short/open protection
• Programmable LED current between 3.0 mA and 30 mA
• 24-Ld 4x4x0.65mm
μQFN Package
Figure 1. 34845 Simplified Application Diagram
34845
34845A/B/C/D
LED DRIVER
98ASA00087D
24-PIN QFN-EP
ORDERING INFORMATION
Device
Temperature
Range (T
A
)
Package
MC34845EP/R2
-40° to 85°C
24 QFN-EP
MC34845AEP/R2
MC34845BEP/R2
MC34845CEP/R2
MC34845DEP/R2
12V
FAIL
PGNDB
34845
SWA
SWB
SWB
VOUT
PGNDA
CH1
CH2
CH3
CH4
CH5
CH6
CH2
CH3
CH4
CH5
CH6
EP
EN
PWM
ISET
VIN
VDC1
VDC2
VDC1
VDC2
COMP
WAKE
~
~
~
~
~
~
~
~
~
~
~
~
OVP
GND
GND
CONTROL
UNIT
5V
Typical Applications
• PC Notebooks
• Netbooks
• Picture Frames
• Portable DVD Players
• Small Screen Televisions
• Industrial Displays
• Medical Displays
• Netbooks
• Picture Frames
• Portable DVD Players
• Small Screen Televisions
• Industrial Displays
• Medical Displays