EPC EPC9509 Hızlı Başlangıç Kılavuzu - Sayfa 2

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QUICK START GUIDE
DESCRIPTION
The EPC9509 is a high efficiency, Zero Voltage Switching (ZVS), class-D
wireless power amplifier demonstration board that operates at 6.78 MHz
(Lowest ISM band). The purpose of this demonstration system is to sim-
plify the evaluation process of wireless power amplifier technology using
eGaN® FETs by including all the critical components on a single board
that can be easily connected into an existing system.
The amplifier board features the enhancement-mode, half-bridge field
effect transistor (FET), the 60 V rated EPC2108 eGaN FET with integrated
synchronous bootstrap FET. The amplifier can be set to operate in either
differential mode or single-ended mode and includes the gate driver/s,
oscillator, and feedback controller for the pre-regulator that ensures
operation for wireless power control based on the A4WP standard. This
allows for testing compliant to the A4WP class 3 standard over a load
range as high as ±50j Ω. The pre-regulator features the 100 V rated 65 mΩ
EPC2036 as the main switching device for a SEPIC converter.
For more information on the EPC2108 eGaN FETs please refer to the data-
sheet available from EPC at www.epc-co.com. The datasheet should be
read in conjunction with this quick start guide.

DETAILED DESCRIPTION

The Amplifier Board (EPC9509)
Figure 1 shows the system block diagram of the EPC9509 ZVS class-D
amplifier with pre-regulator and figure 2 shows the details of the ZVS
class-D amplifier section. The pre-regulator is used to control the ZVS
class-D wireless power amplifier based on three feedback parameters
1) the magnitude of the coil current indicated by the green LED, 2) the
DC power drawn by the amplifier indicated by the yellow LED and 3)
a maximum supply voltage to the amplifier indicated by the red LED.
Only one parameter at any time is used to control the pre-regulator
with the highest priority being the maximum voltage supplied to the
amplifier followed by the power delivered to the amplifier and lastly the
magnitude of the coil current. The maximum amplifier supply voltage
is pre-set to 52 V and the maximum power drawn by the amplifier is
pre-set to 16 W. The coil current magnitude is pre-set to 800 mARMS but
can be made adjustable using P25. The pre-regulator comprises a SEPIC
converter that can operate at full power from 17 V through 24 V.
The pre-regulator can be bypassed by connecting the positive supply
directly to the ZVS class-D amplifier supply after removing jumper JP1 at
location JP1 and connecting the main positive supply to the bottom pin.
JP1 can also be removed and replaced with a DC ammeter to directly
measure the current drawn by the amplifier. When doing this observe
a low impedance connection to ensure continued stable operation of
the controller. Together with the Kelvin voltage probes (TP1 and TP2)
connected to the amplifier supply, an accurate measurement of the
power drawn by the amplifier can be made. The EPC9509 is also provided
with a miniature high efficiency switch-mode 5 V supply to power the logic
circuits on board such as the gate drivers and oscillator.
PAGE 2 |
Table 1: Performance Summary (T
Symbol
V
IN
V
IN
V
OUT
I
OUT
V
extosc
V
Pre_Disable
I
Pre_Disable
V
Osc_Disable
I
Osc_Disable
V
sgnDiff
I
sgnDiff
* Maximum current depends on die temperature – actual maximum current will be subject to switching
frequency, bus voltage and thermals.
The amplifier comes with its own low supply current oscillator that is
pre-programmed to 6.78 MHz ± 678 Hz. It can be disabled by placing
a jumper into JP70 or can be externally shutdown using an externally
controlled open collector / drain transistor on the terminals of JP70 (note
which is the ground connection). The switch needs to be capable of
sinking at least 25 mA. An external oscillator can be used instead of the internal
oscillator when connected to J70 (note which is the ground connection)
and the jumper (JP71) is removed.
| EPC – EFFICIENT POWER CONVERSION CORPORATION |
Demonstration System EPC9509
= 25°C) EPC9509
A
Parameter
Conditions
Also used in
Bus Input Voltage Range –
bypass mode
Pre-Regulator Mode
for logic supply
Amp Input Voltage Range –
Bypass Mode
Switch-Node Output
Voltage
Switch-Node Output
Current (each)
External Oscillator Input
Input 'Low'
Threshold
Input 'High'
Pre-Regulator Disable
Floating
Voltage Range
Pre-Regulator Disable
Floating
Current
Oscillator Disable
Open Drain/
Voltage Range
Collector
Oscillator Disable
Open Drain/
Current
Collector
Differential or Single-Select
Open Drain/
Voltage
Collector
Differential or Single-Select
Open Drain/
Current
Collector
EPC9509 amplifier board photo
WWW.EPC-CO.COM
Min
Max
Units
17
24
V
0
52
V
52
V
1*
A
-0.3
0.8
V
2.4
5
V
-0.3
5.5
V
-10
10
mA
-0.3
5
V
-25
25
mA
-0.3
5.5
V
-1
1
mA
| COPYRIGHT 2015