USB charger data pins
This info is for old or cheap USB chargers. Not smart fast chargers that support QC, PD or other smart charging protocols. Multi-protocol fast chargers are very cheap now a days. This page is if you want to build a cheap, 5V USB charger, or want to understand/research old chargers
There is quite a bit of ambiguity on what to do with data pins on USB chargers before USB fast charge standards. This is because there was no standard. So here are some chargers I took apart, and what they did with their data pins.
Shorting D+ to D- works best for most cases and is what most cheap, non-fast chargers use
Standards
| Standard Downstream Port (Data) | Dedicated Charging Port |
|---|---|
| D+ pin: D+ -> 15kΩ -> GND D+ pin: D+ -> 15kΩ -> GND |
D+ shorted to D-, or any resistance lower than 300Ω Recommended |
* if used for charging-only, modern phones may ignore. USB protocol states, data pins set with 15k to GND, current is limited to 100mA, until more power is requested via data signals
Real charge units
| Brand | Volt | Current | Data pins | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jawbone/Foxlink SPA-K901 AC-DC | 5.0V | 550mA | D-,D+ shorted* | |||||||||||||||||||||
| Generic AC-DC | 5.0V | 550mA | D-,D+ shorted* | |||||||||||||||||||||
| Generic dual-output AC-DC (HLT-1432) | 5.0V | ? | D- pin: 5v ->43.2kΩ -> D- -> 49.9kΩ -> GND D+ pin: 5V -> 43.2kΩ -> D+ -> 49.9kΩ -> GND | |||||||||||||||||||||
| Generic AC-DC (Hoioto/Shenzen Honor) | 5.0V | 1.5A | 0Ω resistor between D- and D+. ie. shorted* | |||||||||||||||||||||
| Generic GA-0502000 AC-DC | 5V | 2A | Shorted* | |||||||||||||||||||||
| Generic 110-240V | 5V +/- 0.5V | 1A +/- 10mA | D+ and D- shorted* | |||||||||||||||||||||
| Car: Point Mobi | 5.1V | 500mA |
D- pin: 5v -> 75kΩ -> D- -> 49.9kΩ -> GND | |||||||||||||||||||||
| Car: AT&T | Shorted* | |||||||||||||||||||||||
| Apple (first gen) ref | 5V | 0.5A | D+ = 2.0V, D- = 2.0V | |||||||||||||||||||||
| Apple (1 A) ref | 5V | 1A | D+ = 2.0V, D- = 2.7V | |||||||||||||||||||||
| Apple (iPhone 3G) ref | 5.0V | 1.5A | D- pin: 5v ->43kΩ -> D- -> 51kΩ -> GND D+ pin: 5V -> 75kΩ -> D+ -> 51kΩ -> GND | |||||||||||||||||||||
| Apple iPad (2.1) refref | 5V | 2.1A | D+ = 2.7V, D- = 2.0V | |||||||||||||||||||||
| Apple (1 A) ref | 5V | 2.4A | D+ = 2.7V, D- = 2.7V | |||||||||||||||||||||
| Samsung (early Galaxy Note) | 5V | D+ = 1.2V, D- = 1.2V | ||||||||||||||||||||||
| Samsung Travel Adapter (ETAOU88JWE) | 5V | 1A | D+ and D- shorted* | |||||||||||||||||||||
| Samsung Travel Adapter (ETAOU61JBE) | 5V | 1A | D+ and D- shorted* | |||||||||||||||||||||
| Samsung Travel Adapter (ETAOU20JBE) | 5V | 0.7A | D+ and D- shorted* | |||||||||||||||||||||
| Garmin PSAIO... | 5V | 1A | D+ and D- shorted* | |||||||||||||||||||||
| Motorola RAZR V3, RIZR, Z8 | See: link | |||||||||||||||||||||||
| PT-5V2A | 5V | 2A | both pins floating(unattached) | |||||||||||||||||||||
| TI TPS251xx chip based chargers | 5V |
these will switch between these modes to find optimal charge rate
| ||||||||||||||||||||||
| Dual USB charger board on ebay in 2024 ref another version | 5V | 3A | shorted | |||||||||||||||||||||
| Single USB Charger board on ebay 2024 ref | 5V | 3A | Resistor configured for Apple specs 2.7V and 2V | |||||||||||||||||||||
* data pins are shorted to each other and are not attached to anything else
References
- https://electronics.stackexchange.com/questions/123172/what-is-the-ideal-way-to-handle-data-pins-d-and-d-on-a-usb-power-adapter-to-be
- https://web.archive.org/web/20170125232305/http://apcmag.com/android-usb-charging-secrets.htm/
- http://ww1.microchip.com/downloads/en/AppNotes/en567019.pdf
- https://www.infineon.com/dgdl/Infineon-AN92554_Implementing_Battery_Charging_Features_using_HX3-ApplicationNotes-v03_00-EN.pdf
- https://electronics.stackexchange.com/questions/123172/what-is-the-ideal-way-to-handle-data-pins-d-and-d-on-a-usb-power-adapter-to-be