User's Manual

18
1.4.8 DPR (Dynamic Power Reduction)
The optional DPR signal is used by wireless devices to assist in meeting regulatory SAR
(Specific Absorption Rate) requirements for RF exposure. The signal is provided by a host
system proximity sensor to the wireless device to provide an input trigger causing a
reduction in the radio transmit output power.
The required value of the power reduction will vary between different host systems and is
left to the host platform OEM and card vendor to determine, along with the specific
implementation details. The assertion and de-assertion of DPR is asynchronous to any
system clock. All transients resulting from the proximity sensor need to be de-bounced by
system circuitry.
(1) State of the DPR
Item State Definition Interpretation
1 Low
Enable the SAR power back off.
Radio is capable of transmitting.
2 High
Disable the SAR power back off,
internally pull up
Radio is incapable of transmitting.
(2) Typical Connection in Platform/System
Remark:
a. The proximity sensor was controlled by the platform side.
b. After DPR pin becomes low level, you can set the MAX TX power by AT commands..