HIGH State

HIGH State

Modulation Depth

100%

LO State

LO State

bq50002

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SLUSBW1A – OCTOBER 2015 – REVISED OCTOBER 2015

7.3 Feature Description

7.3.1 Demodulator

The embedded demodulator outputs at least one valid bit stream under all modulation conditions that can be

used by the accompanied bq500511 controller in order to comply with WPC specification.

More specifically, the WPC worst case condition is defined as the transmitter operating at the minimum

modulation level, and the receiver coil is measured by certain x, y and z axis distance to the center of the

transmitter coil.

Analog demodulation channel function diagram:

•

The diagram below from the WPC spec document explains the concept of Minimum Modulation. The peak-to-

demodulator channel.

•

The difference of the amplitude of the primary cell voltage in the HI and LO state is at least 200 mV.

During a transition the primary cell current and primary cell voltages are undefined. See Figure 3.

Figure 3. Amplitude Modulation of the Power Signal

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