The charge pumps provide fixed +5V, +15V, and -10V for the LCD bias circuits. No external diodes are needed. A high-efficiency, fractional (1.5x/2x) charge pump followed by a low-dropout linear regulator provides +5V to power the source driver. Automatic mode changing achieves the highest conversion efficiency. Two multistage, high-voltage charge pumps generate +15V and -10V to provide VON and VOFF, respectively. Utilizing a unique clocking scheme and internal drivers, these charge pumps eliminate parasitic charge-current glitches and reduce maximum input current, resulting in low electromagnetic emissions. The outputs are sequenced during startup and shutdown. In shutdown, the outputs are discharged to zero.
The high-efficiency inductor step-up converter drives up to 8 white LEDs in series with a constant current to provide backlighting. The series connection allows the LED currents to be identical for uniform brightness and minimizes the number of traces to the LEDs. The MAX1578 regulates constant LED current over the entire temperature range. The MAX1579 features a temperature derating function to avoid overdriving the white LEDs during high ambient temperatures, enabling higher drive current below +42°C.
The MAX1578/MAX1579 are available in space-saving 24-lead 4mm x 4mm thin QFN packages.
|Part Number||Battery Input||Regulation Topology||Max. No. of LEDs||LED Channels||LED Configuration||ILED per Channel|
|PWM Dimming Freq.|
|LED String Volt.|
|MAX1578||1-Cell Li+||Inductor Based||8||1||Series||0.025||200|
|See All LED Drivers (81)|
| 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 and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
|Device||Fab Process||Technology||Sample size||Rejects||FIT at 25°C||FIT at 55°C|