DS1650 Datasheet, PDF (21/26 Pages) National Semiconductor (TI) – Quad Differential Line Receivers

RT1650
Option for GPIO
 Internal pull-up option (pull-up to 3.3V)
 GPIO can be push-pull or open-drain architecture
when GPIO programmed as an output.
 Internal pull-low option
Table 5. RT1650 GPIO Specification
Symbol
Vil
Vih
Description
input logic low voltage
input logic high voltage
Min
Typ
Max
0.8V
2V
5V
Vol
output low voltage
Voh
output high voltage when push-pull architecture
2.6V
3.3V
0.4V
Voh
output high voltage when open-drain
architecture
Hi-Z
Indicator Output
An open-drain output pin, CHG, is provided to indicate
the status of wireless power receiver. The CHG pin can
be connected to a LED for charge status indicator.
When the output of the RT1650 is enabled, the
open-drain N-FET at CHG pin will be pulled to low
level.
Input Over-Voltage Protection
When the input voltage increases suddenly, the
RT1650 adjusts voltage-control loop to maintain
regulator output voltage and sends control error
packets to the transmitter every 30ms until the input
voltage comes back to the VRECT target level (refer to
Dynamic Rectifier Voltage Control Section). Once the
VRECT voltage exceeds its over-voltage threshold
(11.5V typ.), the RT1650 turns on the N-FETs at
CLMP1 and CLMP2 pins to shunt the input current
through external capacitors. By the way the CLAMP
function may affect the communication signal to let the
Tx re-start up.
Over-Temperature Protection
The RT1650 provides an Over Temperature Protection
(OTP) feature to prevent excessive power dissipation
from overheating the device. The OTP function shuts
down the linear regulator operation when the junction
temperature exceeds 150°C. Once the junction
temperature cools down by around 20°C, the receiver
will automatically resume operating.
Foreign Object Detection
The RT1650 is a WPC 1.1.1 compatible device. In
order to enable a power transmitter to monitor the
power loss across the interface as one of the possible
methods to limit the temperature rise of foreign objects,
the RT1650 reports its received power to the power
transmitter. The received power equals the power that
is available from the output of the power receiver plus
any power that is lost in producing that output power
(the power loss in the secondary coil and series
resonant capacitor, the power loss in the shielding of
the power receiver, the power loss in the rectifier). In
WPC1.1.1 specification, Foreign Object Detection
(FOD) is enforced. This means the RT1650 will send
received power information with known accuracy to the
transmitter. The received power is sensed as the
Figure 13.
C_{P PTX,AC}
P_RX,AC ^CS
AC1
RECT
P_RECT
OUT
P_OUT
M
V_RECT
I_OUT
V_S
L_P
L_S
C_D
Rectifier
C_{RECT Regulator}
C_OUT
AC2
Figure 13. Received Power Sensed
Copyright © 2015 Richtek Technology Corporation. All rights reserved.
DS1650-00 July 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
21