EC49024 datasheet(8/9 Pages) E-CMOS

8 / 9 page

QC 2.0 Interface Module

E-CMOS Corp. (www.ecmos.com.tw)

Page 8 of 9

5J15N Rev. F001

EC49024

Quick Charge 2.0 Interface

At power-up EC49024 turns on switch N5 (see Figure 3) 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 EC49024 starts

monitoring the voltage level at D+. If it continuously stays At USB cable disconnect the voltage level at D+ above

VDAT(REF) (typ. 0.325 V) and below VSEL(REF) (typ. 2 V) for at least 1.25 seconds EC49024 will enter Quick Charge 2.0

operation mode. If the voltage at D+ drops any time below 0.325 V EC49024 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 EC49024 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 EC49024 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.

For Quick Charge 2.0 Class A support only, the V3 pin has to be connected to the BYPASS pin (directly or through a

resistor up to 100 kΩ). This will inhibit any requests for setting a 20 V output.is pulled down by resistor R

DAT(LKG) (see

Figure 1). Once it drops below 0.325 V EC49024 will turn on switch N5 (thereby short-circuiting D+ and D-) and turns

off switches N1 to N4. This sets the default output voltage of 5 V. The recommended value for RDAT(LKG) = 390 kΩ.

Vo1(5V)=VFB*((R1/R2)+1);

Vo2(9V)= VFB*((R1/ RX1)+1), RX1=R2//R3;

Vo3(12V)= VFB*((R1/ RX2)+1), RX2=RX1//R4;

Vo4(20V)= VFB*((R1/ RX3)+1), RX3=RX2//R5;

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