|
|
|
MAX1895, MAX1995
High-Efficiency, Wide Brightness Range, CCFL Backlight Controllers
|
Status
Description
The MAX1895/MAX1995 integrated controllers are optimized to drive cold-cathode fluorescent lamps (CCFL) using a synchronized full-bridge inverter architecture. Synchronized drive provides near sinusoidal waveforms over the entire input range to maximize the life of CCFLs. The controllers also operate over a wide input voltage range with high efficiency and broad dimming range.
The MAX1895/MAX1995 include safety features that limit the transformer secondary voltage and protect against single-point fault conditions including lamp-out and short-circuit faults.
The MAX1895/MAX1995 regulate the CCFL brightness in three ways: linearly controlling the lamp current, digital pulse-width modulating (DPWM) the lamp current, or using both methods simultaneously to achieve the widest dimming range (>30:1). CCFL brightness can be controlled with either an analog voltage (both MAX1895 and MAX1995) or a two-wire SMBus compatible interface (MAX1895 only).
The MAX1895/MAX1995 directly drive the four external N-channel power MOSFETs of the full-bridge inverter. An internal 5.3V linear regulator powers the MOSFET drivers, the synchronizable DPWM oscillator, and most of the internal circuitry. The MAX1895/MAX1995 are available in the space-saving 28-pin thin QFN package and operate over the -40°C to +85°C temperature range.
|
|
Data Sheet
|
An evaluation kit is available: MAX1895EVSYS, MAX1995EVSYS
Key Features
- Synchronized-to-Resonant Frequency
- Good Crest Factor for Longer Lamp Life
- Ensures Maximum Strike Capability
- High Power to Light Efficiency
- Wide Dimming Range (3 Methods)
- Lamp Current Adjust: >3 to 1
- Digital PWM (DPWM): >10 to 1
- Combined: >30 to 1
- Feed-Forward for Fast Response to Step Change of Input Voltage
- Wide Input Voltage Range (4.6V to 28V)
- Transformer Secondary Voltage Limiting to Reduce Transformer Stress
- Lamp-Out Protection with 2s Timeout
- Short-Circuit and Other Single-Point Fault Protections
- Synchronizable DPWM Frequency
- Dual-Mode Brightness Control Interface
- SMBus Serial Interface (MAX1895 Only)
- Analog Interface (Both Devices)
- High-Accuracy Analog Interface
- Separate 100% Brightness Voltage Reference Pin (CRFSDA)
- Separate Minimum Lamp-Current Set-Point Pin (MINDAC)
- Small Footprint 28-Pin Thin QFN (5mm x 5mm) Package
|
|
Applications/Uses
- Car-Navigation Displays
- LCD Monitors
- Notebook Computers
- Point-of-Sale Terminals
- Portable Display Electronics
|
|
|
|
Key Specifications:
| CCFL Controllers |
| Part Number |
VIN (V) |
VIN (V) |
Topology |
Channels |
Dimming Interface |
Freq. |
EV Kit |
Package/Pins |
Oper. Temp. (°C) |
| min |
max |
| MAX1895 |
4.6 |
28 |
Full-Bridge |
1 |
|
Fixed PWM |
Yes |
|
-40 to +85 |
|
See All CCFL Controllers (14)
|
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
|
|
Diagram
Functional Diagram
Didn't Find What You Need?
Information Index
Document Ref.: 19-2157
Rev 1;
2002-11-08
This page last modified: 2009-10-15
|
|
|