P9027LP-R Datasheet

© 2016 Integrated Device Technology, Inc

15

April 28, 2016

accomplished internally through sensing circuitry and then digitized by ADC. The current sensing does not vary with the temperature. Refer to

the Electrical Characteristic Table for current sense accuracy. The internal current sensing accuracy degrades during light-load conditions.

When the over-current limit is tripped, the P9027LP-R sends End of Power Transfer Over-Current packet (EPT: OC) to the P9235A-R,

shutting down the entire system. In the event the transmitter fails to recognize the packet, the receiver will continue sending the EPT: OC

packet up to 12 times.

The OC limit is typically set to ~24% higher than maximum load. Please refer to

Table 8 below for different current protection thresholds.

Table 8. Resistor Value, Over-current Setting

Resistor ( KΩ )

IOC Limit

Max. Output Current

GND

Disabled

-

2.26

260mA

200mA

6.19

540mA

400mA

9.53

780mA

600mA

Enable pin - ������������

The enable pin (

EN ) is an active low logic. When connected to logic high, the receiver shuts down by sending an End of Power Transfer

(EPT) packet to P9235A-R and forces the OUT pin to high impedance state. When connected to a logic low, the device operates in normal

mode.

Active Flag pin - ������������������

The

ACT pin is an open drain output indicator. Connect a LED from this pin to OUT to indicate connection between the receiver and the

transmitter has been established and the power is being transferred.

Interrupt pin - ������������������

The P9027LP-R provides an open-drain, active low interrupt output pin. It is asserted high when

EN is high, EOC is logic high, die

temperature reaches 130°C, TS1 or TS2 and thermal shutdown have been triggered. During normal operation, the

INT pin is pulled high.

This pin can be connected to the interrupt input of a microcontroller. The source of what triggered the interrupt is available in I2 C register.

End of Charge - EOC

The End of Charge feature is a dedicated pin that forces the P9235A-R to terminate power transfer when the EOC is logic high. When EOC is

asserted, the device issues an End Power Transfer (EPT) packet to the transmitter terminating all activities by placing P9235A-R into standby

mode. The P9235A-R will start digital ping after five minutes or if the P9027LP-R is removed.

Remote Temperature Sensing

The P9027LP has two temperature sensor inputs, TS1 and TS2 that can be used to monitor two remote locations such as the battery and the

Rx coil. It is recommended to use an NTC thermistor typical 10 kΩ, depending on the temperature range of interest (0 kΩ – 18 kΩ). The basic

characteristic of an NTC thermistor is given below for reference.































0

0

T

1

T

1

B

exp

R

R

Where: