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6 | | EPC – EFFICIENT POWER CONVERSION CORPORATION |
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| COPYRIGHT 2018
Demonstration System EPC9129
2. With power off, connect the main input power supply bus +V
IN
to the
bottom pin of JP1 and the ground to the ground connection J1 as
shown in figure 8.
3. With power off, connect the control input power supply bus to J1. Note
the polarity of the supply connector. This is used to power the gate
drivers and logic circuits.
4. Make sure all instrumentation is connected to the system.
5. Turn on the control supply – make sure the supply is 19 V range.
6. Turn on the main supply voltage to the required value (it is recommended
to start at 0 V and do not exceed the absolute maximum voltage of 80 V).
7. Once operation has been confirmed, adjust the main supply voltage
within the operating range and observe the output voltage, efficiency
and other parameters on both the amplifier and device boards.
8. For shutdown, please follow steps in the reverse order. Start by reducing
the main supply voltage to 0 V followed by steps 6 through 2.
NOTE.
1. When measuring the high frequency content switch-node (Source Coil Voltage), care
must be taken to avoid long ground leads. An oscilloscope probe connection (preferred
method) has been built into the board to simplify the measurement of the Source Coil
Voltage (shown in figure 11).
2. AVOID using a Lab Benchtop programmable DC as the load for the category 3 and
category 5 device boards. These loads have low control bandwidth and will cause
the EPC9129 system to oscillate at a low frequency and may lead to failure. It is
recommended to use a fixed low inductance resistor as an initial load. Once a design
matures, a post regulator, such as a Buck converter, can be used.
Go to
www.epc-co.com
periodically for updates on new wireless power device demon-
stration boards capable of delivering a regulated output.
THERMAL CONSIDERATIONS
The EPC9129 demonstration system showcases the EPC8010, EPC2019,
EPC2038, and EPC2016C in a wireless energy transfer application.
Although the electrical performance surpasses that of traditional
silicon devices, their relatively smaller size does magnify the thermal
management requirements. The operator must observe the temperature
of the gate driver and eGaN FETs to ensure that both are operating within
the thermal limits as per the datasheets.
NOTE. The EPC9129 demonstration system has limited current and thermal protection
only when operating off the Pre-Regulator. When bypassing the pre-regulator there is no
current or thermal protection on board and care must be exercised not to over-current or
over-temperature the devices. Excessively wide coil coupling and load range variations
can lead to increased losses in the devices.
Pre-Cautions
The EPC9129 demonstration system has no enhanced protection
systems and therefore should be operated with caution. Some specific
precautions are:
1. Never operate the EPC9129 system with a device board that is AirFuel
compliant as this system does not communicate with the device
to correctly setup the required operating conditions and doing so
can lead to failure of the device board. Please contact EPC should
operating the system with an AirFuel compliant device be required
to obtain instructions on how to do this. Please contact EPC at
should the tuning of the coil be required to suit
specific conditions so that it can be correctly adjusted for use with the
ZVS class-D amplifier.
2. There is no heat-sink on the devices and during experimental
evaluation it is possible present conditions to the amplifier that may
cause the devices to overheat. Always check operating conditions and
monitor the temperature of the EPC devices using an IR camera.
3. Never connect the EPC9512 amplifier board into your VNA in an
attempt to measure the output impedance of the amplifier. Doing so
will severely damage the VNA.
Figure 3: Diagram of EPC9512 ZVS class-D amplifier circuit.
Figure 2: Block diagram of the EPC9512 wireless power amplifier.
+
V
AMP
Q
1_a
L
ZVS12
Q
2_a
Q
1_b
Q
2_b
L
ZVS2
C
ZVS2
C
ZVS1
L
ZVS1
Coil connection
Single
Ended
Operation
Jumper
Pre-regulator
Pre-regulator
jumper
JP1
J1
V
IN
Bypass mode
connection
ZVS class D
SEPIC
Pre-regulator
amplifier
19 V
DC
4 V
DC
–
80 V
DC
Cs
Coil
X
Iamp
Pamp
Vamp
Icoil
Combiner
Control reference signal
Icoil