Avago Technologies ACPL-P347-000E - Manual (Page 6)

6
Power Supply Schemes
The Evaluation board is designed with DC supply flexibility in mind and a total of 7 different power supply schemes are
possible (See Table 1).
Table 1. Power Supply Schemes
Scheme Vcc1 Vcc2a Veea S2a S3a D4a/ R7a Vcc2b Veeb S2b S3b D4b/ R7b Remarks
1 +5V
External
+15V~30V
External
0V s/c s/c NM Bootstrapped*
from Vcc2a
(+15V~30V)
0V s/c s/c NM Default (simplest)
- 2 external supplies needed
for Vcc1 & Vcc2a
2 +5V
External
+15V~30V
External
0V s/c s/c NM +15V~30V
External
0V s/c s/c NM Higher Power
- 3 external supplies needed
for Vcc1, Vcc2a & Vcc2b
3 +5V
External
+15V~30V
External
(15V |-0V~ -15V)
open open 15V/1k +15V~30V External
(15V |-0V~ -15V)
open open 15V/1k Vee available
- 2 external supplies needed
for Vcc1, Vcc2a & Vcc2b
- Virtual gnds Vea & Veb
generated thru D4 &R7
4 +5V
External
DC/DC
(=Vcc1/+15V)
0V s/c s/c NM Bootstrapped*
from Vcc2a
(+15V)
0V s/c s/c NM Cheap
- Only 1 external supply is
needed (Vcc1)
- 1 Single o/p DC/DC con-
verter for Vcc2a
5 +5V
External
DC/DC
(=Vcc1/+15V)
0V s/c s/c NM DC/DC
(=Vcc1/+15V)
0V s/c s/c NM Higher Power
- Only 1 external supply is
needed (Vcc1)
- 2 Single o/p DC/DC convert-
ers for Vcc2a & Vcc2b
6 +5V
External
DC/±DC
(=Vcc1/±15V)
(+15V |-15V)
open s/c NM DC/±DC
(=Vcc1/±15V)
(+15V |-15V)
open s/c NM Vee available
- Only 1 external supply is
needed (Vcc1)
- 2Dual o/p DC/DC converters
for Vcc2a,Vcc2b,Veea & Veeb
7 +5V
External
DC/±DC
(=Vcc1/±9V)
(+15V |-3V)
open open 15V/1k DC/±DC
(=Vcc1/±9V)
(+15V |-3V)
open open 15V/1k Vee available
- Only 1 external supply is
needed (Vcc1)
- Dual o/p DC/DC converters
for Vcc2a & Vcc2b
- Virtual gnds Vea & Veb
generated thru D4 & R7
Since TVS D2 voltage is selected at a breakdown voltage of 18V, both Vcc2 and Vee voltage are not advisable to set at voltage beyond ±15V.
To use a voltage higher than 15V, please replace D2 will a bigger clamping voltage.)
Descriptions of each of the 7 different power supply schemes are provided below. Users are encouraged to evaluate all
seven schemes to decide which one is most suitable for his/her needs:
Power scheme 1 - This simple scheme uses two power supplies. A +5V isolated DC supply is supplied externally to power
the low voltage Vcc1 circuit. Another external supply (+15V~30V for Vcc2a) is needed for the gate driver driving the IGBT
or SiC/GaN MOSFET at bottom inverter arm. Vcc2b supply is obtained from Vcc2a by bootstrapping operation. For this
to work, the bootstrap components D3b and R6 must be connected, all S2 jumpers must be shorted so that no nega-
tive supply of Vee is allowed, and the Signal input 2 should be 180 ° out of phase to signal input 1. All S2’s are shorted
to connect Vee to Ve so that negative supplies are not present. S3’s are shorted by default but it has no effect on actual
operation of the board. (Please contact Avago Technologies if more information on bootstrapping is required.)
Power scheme 2 - Similar to scheme 1 in terms of Vcc1 and Vcc2a supplies with the addition of a third external supply
(+15V~30V) for Vcc2b. This is necessary when IGBT or SiC/GaN MOSFETs get bigger demanding more driving power.
Suitable for use when Qg of IGBT or SiC/GaN MOSFET rises above 200nC. (Bootstrapped power supplys can only handle
low driving power.)
Power scheme 3 - This scheme uses 3 external supplies at Vcc1, Vcc2a and Vcc2b with the added advantage of negative
supplies for Vee (or Veea & Veeb) by introducing a 15V zener at D4 and R7 of around 1kOhm to provide proper biasing
current at D4. For this scheme to work, both S2 and S3 jumpers must be open while the external supplies (+15V~24V) at
high voltage driver side are to be connected across Vcc2 and Vee pins only, not Ve pin. As the external supply changes
from +15V to +24V, Vcc2 will stay at +15V, but Vee changes from -0V to -15V, all with reference to virtual ground at Ve.