Datasheet

TPS2540, TPS2540A
TPS2541, TPS2541A
SLVSAG2C –OCTOBER 2010– REVISED OCTOBER 2011 www.ti.com
Logic Control Modes
Both the TPS2540/40A and TPS2541/41A support the listed standards above for the SDP, CDP and DCP modes
using the CTL1, CTL2, and CTL3 logic I/O control pins, although their truth tables are different as shown below.
The different CTLx settings correspond to the different types of charge modes. Also, using the Auto-Detect
Mode, the Divider Mode or BC1.2 / YD/T 1591-2009 can be automatically selected without external user
interaction.
NOTE
With the TPS2540/40A, if the “000” mode is selected, the power switch will be turned off
and an output discharge resistor will be connected, while the data line switches will be
turned off.
Table 2. TPS2540/40A Control Truth Table
CTL1 CTL2 CTL3 MODE
0 0 0 OUT discharge, power switch OFF.
0 X 1 Dedicated charging port, auto-detect.
X 1 0 Standard downstream port, USB 2.0 Mode.
1 0 0 Dedicated charging port, BC1.2 only.
1 0 1 Dedicated charging port, Divider Mode only.
1 1 1 Charging downstream port, BC1.2.
Table 3. TPS2541/41A Control Truth Table
CTL1 CTL2 CTL3 MODE
0 0 X Dedicated charging port, auto-detect.
0 1 X Dedicated charging port, BC1.2.
1 0 X Dedicated charging port, Divider Mode only.
1 1 0 Standard downstream port, USB 2.0 Mode.
1 1 1 Charging downstream port, BC1.2.
Output Discharge
To allow a charging port to renegotiate current with a portable device, TPS2540/40A/41/41A uses the VBUS
discharge function. It proceeds by turning off the power switch while discharging OUT, then turning back ON the
power switch to reassert the OUT voltage.
This discharge function is automatically applied when a change at the CTLx lines results in any of the following
mode transitions.
• Any transition to and from CDP
• Any transition to and from SDP
In addition to this, a direct discharge control, DSC, is available with the TPS2541/41A, while with the
TPS2540/40A, a discharge can be achieved using the mode “000”.
Overcurrent Protection
When an over-current condition is detected, the device maintains a constant output current and reduces the
output voltage accordingly. Two possible overload conditions can occur. In the first condition, the output has
been shorted before the device is enabled or before V
IN
has been applied.
The TPS2540/40A/41/41A senses the short and immediately switches into a constant-current output. In the
second condition, a short or an overload occurs while the device is enabled. At the instant the overload occurs,
high currents may flow for nominally one to two microseconds before the current-limit circuit can react. The
device operates in constant-current mode after the current-limit circuit has responded. Complete shutdown
occurs only if the fault is present long enough to activate thermal limiting. The device will remain off until the
junction temperature cools approximately 10°C and will then re-start. The device will continue to cycle on/off until
the over-current condition is removed.
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Product Folder Link(s): TPS2540, TPS2540A TPS2541, TPS2541A