Simplified Block Diagram
Click any title below to view the detail page where available.
- 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
- Car-Navigation Displays
- LCD Monitors
- Notebook Computers
- Point-of-Sale Terminals
- Portable Display Electronics
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.