IP Phones encounter a multitude of power management challenges and Kinetic Technologies provides advanced application solutions. IP phones are powered through their Ethernet connection, which require PoE controllers to supply regulated voltage rails for phone operation. Ancillary functions require additional power management solutions to power specific circuit requirements for display backlighting, RGB LED indicator lamp drivers, buck and boost converters, load switching and Ethernet port EMI suppression.
LCD Backlight LED Drivers
IP Phone LCD displays are illuminated by LED backlighting. White LEDs are used for color LCD displays and lower cost IP phones use monochrome displays with either white or other fixed color LEDs. Backlight LED strings are configured in series or series/parallel configurations that often require the supply voltage to be boosted from the PoE source. Multiple current sink drivers connect to long serial strings of WLEDs and therefore require a compliance voltage significantly higher than the battery voltage.
Panel size and resolution determine the number of white LEDs (WLED) required to produce the necessary screen brightness
Dimming techniques to control the brightness can range from simple linear LED brightness control to sophisticated high efficiency PWM control to achieve contrast ratios of typically 20,000:1
High accuracy current sinks to provide uniform backlight across larger panel sizes
High efficiency boost power conversion required to minimize demands on battery power consumption and maximize the battery life between charge cycles
Multiple series/parallel strings of WLED drivers to match the display panel needs
Multiple programming options from simple PWM signal control to full-featured I2C interfaces.
Advanced design, low drop-out current sinks with tight linearity characteristics to maintain constant LED current accuracy over all battery voltage extremes
High efficiency boost converters with integrated protection against LED open and short-circuit conditions
Load Switch with OVP and Reverse Polarity Protection
RGB LED Drivers
IP Phones use multicolor RGB LEDs for indicator lamps. Indicator lamps show power on/off or function status. Implementing indicator lamp LED control circuits to interface LED control switching to microcontroller logic is a tedious design process and requires multiple discrete components.
RGB LED drivers allow simplified programmable control of LED color and brightness
3-channel RGB LED drivers permit custom color control
4-channel RGBW devices allow for driving a white LED in addition to the RGB LED
Multiple programming options include I2C or ExpressWire to ease integration with a wide variety of processors and operating systems
Wide range of ramp up/down timing for slow fade in/out effects and complex repeating patterns
PoE controllers used in IP Phone applications do not always provide all the specific voltage rails needed by specific application circuits. Voltage regulators allow available voltage rails to be stepped up or down at the point of load for specific application circuits.
For light load current requirements, a dual output linear regulator provides a compact, low- cost solution
When high power conversion efficiency is desired, a DC/DC switching regulator can be a better choice. DC/DC switching regulators are available for voltage step-up and step-down applications
PoE driven IP Phones End typically require high efficiency power conversion, in the smallest space with minimum component count. Kinetic Technologies offers a solution that integrate the PD physical interface with a DC/DC controller function in a single package, supporting single outputs with power levels from a few watts up to 30W.
The KTA1137A supports single output isolated or non-isolated solutions for IEEE802.3af (Type 1) and IEEE802.3at (Type 1 and Type 2) PDs or higher power levels, either by using custom programmed PSEs or by implementing the LLDP to enable 4-pair power delivery on the Ethernet cable. The KTA1137A includes input and output over-current protection, output over-voltage protection, and over-temperature protection.
13W/30W 802.3af/at PoE PD and Integrated DC-DC Controller
Kinetic Technologies’ EMI/ESD Suppression solution is the industry’s first of its kind, integrating ESD and Common Mode EMI suppression IC to improve EMC performance in Ethernet applications. It is built around Kinetic Technologies’ patented and proprietary Active EMC suppression technology to enable a “Design for Compliance” approach to system design right from the start. This product helps eliminate EMC compliance challenges by providing consistent EMC performance and improvements utilizing silicon-based technology as opposed to passive technologies. EMI/ESD suppression by Kinetic Technologies enables system designers to comply with:
CISPR22 and FCC Part 15, Class B requirements for Radiated and Conducted Emissions
IEC 61000-4-3/6 requirements for Radiated and Conducted Immunity, Level 3 or higher