USER GUIDE
UG499: Si828x-AW-GDB Gate Driver Boards
Skyworks Solutions, Inc. • Phone [949] 231-3000 • [email protected] • www.skyworksinc.com
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4
November 10, 2022
Table 1: Input I/O Connector (Low Voltage JT3)
•
PWM Signals:
High-side and low-side PWM are RS-422 compatible differential inputs. The termination impedance of the
differential receiver is 120
Ω
.
•
FAULT Signal:
The fault signal is an RS-422 compatible differential output with a maximum drive strength of 20mA. A high
signal (positive line > negative line) means there are no fault conditions for either gate driver channel. This signal will be
low if an overcurrent fault or UVLO fault condition is detected on either channel. A red LED will indicate a fault condition.
The LED, DT6, indicates a high-side fault and DT8 indicates a low-side fault.
•
UVLO Fault:
The UVLO circuit detects when the output rails of the isolated DC/DC converter fall below safe operating
conditions for the gate driver. A UVLO fault indicates that the potential between the split output rails has fallen below
the UVLO active level. The gate for the channel where the fault occurred will be pulled low through RG for the duration
of the fault regardless of the PWM input signal. The fault will automatically clear once the potential has risen above the
UVLO inactive level. There is hysteresis for this fault to ensure safe operating conditions. The UVLO faults for both chan-
nels are combined along with the over-current fault in the FAULT output signal. When there is no UVLO fault present, a
green LED indicates a power good state. The LED, DT5, indicates a high-side power good status and DT7 indicates a low-
side power good status.
•
Over-Current Fault:
An over-current fault is an indication of an over-current event in the SiC power module. The overcur-
rent protection circuit measures the drain-source voltage, and the fault will indicate if this voltage has risen above a
level corresponding to the safe current limit. When a fault has occurred the corresponding gate driver channel will be
disabled, and the gate will be pulled down through a soft-shutdown resistor, RSS. The drain-source limit can be config-
ured through on-board resistors. The over-current fault is latched upon detection and must be cleared by the user with a
high pulse of at least 500 ns on the RESET signal.
•
RTD (NTC):
RTD output is a differential signal that returns the resistance of the temperature sensor (NTC) integrated into
XM3 modules. The signal is a frequency modulated signal that encodes the resistance of the temperature sensor. The
approximate temperature of the module can be determined from this resistance. See the section RTD (NTC) Temperature
Feedback for further details.
Pin Number
Parameter
Description
1
VDC
Power supply input pin (+12 V Nominal Input)
2
Common
Common
3
HS-P
Positive line of 5 V differential high-side PWM signal pair. Terminated Into 120
Ω
4
HS-N
Negative line of 5 V differential high-side PWM signal pair. Terminated into 120
Ω
5
LS-P
Positive line of 5 V differential low-side PWM signal pair. Terminated into 120
Ω
6
LS-N
Negative line of 5 V differential low-side PWM signal pair. Terminated into 120
Ω
7
FAULT- P
Positive line of 5 V differential fault condition signal pair. Drive strength 20 mA. A low state on FAULT indicates when
a desaturation fault has occurred. The presence of a fault precludes the gate drive output from going high.
8
FAULT- N
Negative line of 5 V differential fault condition signal pair. Drive strength 20 mA. A low state on FAULT indicates
when a desaturation fault has occurred. The presence of a fault precludes the gate drive output from going high.
9
RTD-P
Positive line of 5 V temperature dependent resistor output signal pair. Drive strength 20 mA. Temperature measure-
ment is encoded via frequency.
10
RTD-N
Negative line of 5 V temperature dependent resistor output signal pair. Drive strength 20mA. Temperature mea-
surement is encoded via frequency.
11
PS-DIS
Pull down to disable power supply. Pull up or leave floating to enable. Gate and source are connected with 10 k
Ω
when disabled.
12
Common
Common
13
PWM EN
Pull down to disable PWM input logic. Pull up or leave floating to enable. Gate driver output will be held low
through turn-off gate resistor if power supplies are enabled.
14
Common
Common
15
RESET
When a fault exists, bring this pin high to clear the fault.
16
Common
Common
Note:
Inputs 3 to 10 are differential pair.
