Design Con 2015

Power Integrations teams with Qualcomm on rapid-charging technology for mobile devices

-August 01, 2013

The CHY100 IC enables smart AC-DC wall chargers for Qualcomm Quick Charge 2.0 platform; cuts charge times for smartphones and tablets by up to 75%

Power Integrations introduced the CHY100 that, it claims, is the first AC-DC wall-charger interface IC that enables designers of mobile devices to implement the Quick Charge 2.0 protocol from Qualcomm. Quick Charge 2.0 enables users to charge mobile devices up to 75% faster than when using conventional technology.

 
 

Figure 1: Functional block diagram

 

Quick charge 2.0 interface

At power-up CHY100 turns on switch N5 (see Figure 1) in 20 ms or less after the BYPASS pin voltage has reached 4 V. Switch N4 and output switches N1 to N3 remain off. This sets the default 5 V output voltage level. With D+ and D- short-circuited the normal handshake between the AC-DC adapter (DCP) and powered devices (PD) as described in the USB Battery Charging Specification 1.2 can commence.

After switch N5 has been turned on CHY100 starts monitoring the voltage level at D+. If it continuously stays above 0.325 V for at least 1.25 seconds CHY100 will enter Quick Charge 2.0 operation mode. If the voltage at D+ drops any time below 0.325 V CHY100 resets the 1.25 seconds timer and stays in USB Battery Charging Specification 1.2 compatibility mode with a default output voltage of 5 V.

 

Once CHY100 has entered Quick Charge 2.0 operation mode switch N5 will be turned off. Additionally switch N4 is turned on connecting a 19.53 kΩ pull-down resistor to D-. As soon as the voltage at D- has dropped low (<0.325 V) for at least 1 ms CHY100 starts accepting requests for different AC-DC adapter output voltages by means of applied voltage levels at data lines D+ and D- through the powered device. Table 1 summarizes the output voltage lookup table, corresponding AC-DC adapter output voltages and status of switches N1 to N3.

 

 
 

 

The CHY100 with traditional output regulation including optocoupler and secondary reference regulator TL431

Used in combination with Power Integrations’ AC-DC switcher ICs, the charger incorporates all the necessary elements required to add Quick Charge 2.0 functionality to AC-DC wall chargers. The device detects commands from a Quick Charge 2.0-enabled device, such as a cellphone handset, and adjusts the output of the AC-DC wall charger to enable increased power delivery to the device’s battery.

When plugged into a powered device without Quick Charge 2.0 capability, the IC automatically disables the higher-voltage/higher-power capability to ensure safe operation. Tests confirm that smartphones with high-capacity batteries can be fully charged in as little as one hour using Quick Charge 2.0 – an impressive improvement from the four-hour charging cycles characteristic of conventional fixed-voltage chargers.

 

Typical application schematic

 

This is a spec-compliant, production-ready IC for AC-DC wall adapters enabling OEMs and adapter makers to implement Quick Charge 2.0 immediately. Qualcomm's Quick Charge 2.0 allows mobile devices to be charged up to 75% faster and it is rapidly becoming the industry-wide standard for cell phones and tablets.

 
  

The IC is suitable for battery chargers for smartphones, tablets, netbooks, digital cameras and Bluetooth® accessories as well as USB power output ports. Devices are available in SOIC-8 packaging and cost $0.22 each in 10K quantities. Visit http://www.powerint.com/CHY100 for more information.

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