MaxCharge are trademarks of Texas Instruments Incorporated.
USB Type-C is a registered trademark of Texas Instruments Incorporated.
All trademarks are the property of their respective owners.
The USB Battery Charging Specification 1.2 (BC1.2) specification defines the mechanisms to permit USB devices to draw current higher than standard USB current such 500 mA for USB2.0, 900 mA for USB3.0. Through the mechanism defined in the BC1.2 spec, devices can draw up to 1.5 A of current. The detection and the advertisement of the higher current capable ports are done through USB2.0 D+ and D- lines upon connection. There are three charging ports defined in the BC1.2 spec:
Table 1-1 shows the most common USB 1.2 port types.
Port Definition | Examples | Output Current |
---|---|---|
SDP (Standard Downstream Port) | Laptop USB port | 5 V at 100mA (USB 2.0) 5 V at 500 mA (USB2.0) 5 V at 900 mA (USB3.0) |
DCP (Dedicated Charging Port) | USB Wall adapter | 5 V at 500 mA to 1.5 A |
CDP (Charging Downstream Port) | Audio Docking Station | 5 V at 900 mA to 1.5 A |
To achieve fast charging, high voltage (9 V/12 V) adapter with USB compatibility (5 V) is required. TI refers such adapters as HVDCP (High Voltage Dedicated Charging Port) in general. Several companies have proprietary handshake to achieve this goal. It also includes TI-defined proprietary handshake MaxCharge™.
When DCP is detected, the charger can initiate adjustable high-voltage adapter handshake including MaxCharge and so on. The handshake connects combinations of voltage source(s) and/or current sink on D+/D- to signal input source to raise output voltage from 5 V to 9 V / 12 V with up to 1.5 A current capability.
Table 2-1 shows other popular USB D+/D- input current limit detection types.
Port Definition | Examples | Output Current |
---|---|---|
Non-Standard Adapters | Certain market adapters | 5 V at 1 A / 2.1 A / 2.4 A |
HVDCP (High Voltage Dedicated Charging Port) | MaxCharge™ adapter | 5 V / 9 V / 12 V at 1.5 A |
USB Type-C at 1.5 A | - | 5 V / 1.5 A |
USB Type-C at 3 A | - | 5 V / 3 A |
USB PD (Power Delivery) | - | Up to 20 V / Up to 5 A |
Table 3-1 shows D+/D- input current limit detection capability comparison among single cell switching battery charger devices.
USB D+/D- detection | Devices |
---|---|
SDP (USB100, USB500), DCP, CDP | BQ24190, BQ24195/L |
SDP (USB100, USB500), DCP, Non-Standard Adapters (3 options) | BQ24297 |
SDP (USB500), DCP, Non-Standard Adapters (3 options) | BQ24295 |
SDP (USB500), DCP, Non-Standard Adapters (4 options) | BQ25601D, BQ25600D, BQ25611D |
SDP (USB500), DCP, Non-Standard Adapters (4 options) (Standalone single-cell chargers with ILIM pin) | BQ25606, BQ25616 |
SDP (USB500), DCP, CDP, Non-Standard Adapters (4 options), HVDCP | BQ25890, BQ25895 |
SDP (USB500), DCP, CDP, Non-Standard Adapters (4 options), HVDCP, Programmable D+/D- Drivers for Non-Standard Adapter handshake | BQ25890H, BQ25898D |