P9412 Datasheet

R35DS0011EU0120 Rev.1.2

Jul.6.21

Page 14

3.4

Multiple-Time Programmable Memory

The P9412 includes Multiple-Time Programmable (MTP) memory, or pseudo-flash, that can be re-programmed

up to 1000 times. This offers the flexibility of re-programming during pre-production to optimize performance

and/or re-programming for field upgrades after product release. The device contains 24kB of MTP memory. The

MTP programming voltage range is based on the USB “On-the-Go” (OTG) specification of 5V power (±10%)

applied to VRECT via the CPOUT pin.

3.5

Tx Mode

When the P9412 operates as a wireless power transmitter (Tx), power is applied to the VOUT pins as the input,

which is the same node as the power receiver (Mobile Device) output when the device operates in WPC Rx

Mode. In Tx Mode (Base Station), the Rx is now the Tx and sends instructions that are filtered using the DEMOD

filter shown in Figure 5 and decoded internally using a dithered PWM controller for high-resolution voltage

modulation decoding. Based on the received packet, the P9412 will adjust the operating frequency to match the

transmitted power level to the required receiver power level for reliable and efficient wireless power transfer.

Figure 5. Tx DEMOD Filter and AC Coupling

3.6

Synchronous Rectifier

The efficiency of the full-bridge rectifier in the P9412 is increased by integrating a synchronous rectifier. The

rectifier comprises four internally-driven switches that work in a full synchronous mode when the load applied to

CPOUT is higher than the programmed threshold value. Below that threshold, the rectifier works in half-

synchronous rectification mode. In half-synchronous rectification mode, only the low-side N-MOSFETs are

switching and the high-side N-MOSFETs are forced into diode mode. At power-up, when the voltage on VRECT is

below the UVLO threshold, the rectifier works by using the MOSFET body diodes to rectify incoming AC voltage

to DC voltage. The BST capacitors are used to provide power to drive the gates of the high-side NMOS switches

in full-synchronous operating mode.

3.6.1.

VRECT Voltage Range

Once VRECT powers up to greater than UVLO, the full-bridge rectifier switches to half-synchronous or full-

synchronous mode (based on the loading conditions) to efficiently transfer energy from the transmitter to the

load on CPOUT. The control loop of the P9412 maintains the rectifier voltage between 5V and 21.5V, depending

on the output current (IOUT) and the programmed output voltage. VRECT must not be directly loaded.

3.6.2.

Over-Voltage Protection

In the event that the

VRECT voltage increases above the OVP voltage threshold, the P9412 sends an interrupt

to the system applications processor (AP), initiates internal self-clamping (PCLAMP), external PCLAMP_DR

clamping, and sends control error packets/frequency increment commands to the transmitter in an attempt to