EPC 9104 Schnellstart-Handbuch - Seite 12

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c. Operation using direct gating signal control

This method of operating the wireless system is similar to opera-

tion using an external oscillator except the user now directly con-

trols the gating signals. It is important to note that the user MUST

provide the necessary dead-time between the high side (29 ns

recommended) and low side (18 ns recommended) signals and

also ensure that both gating signals cannot be high at the same

time as these features have not been built into the circuit when

sourcing the gating signals directly. This has been an intentional

omission allowing users to integrate their custom circuits to as

close to their needs as possible. With this method the entire phase

follower feedback circuit is bypassed.

1. Prior to connecting the source board to the source coil, resis-

tors R16 (0 , size 0603) and R17 (0 , size 0603) must be re-

moved from the board. Resistors R18 (10 k , size 0603) and

R19 (10 k , size 0603) must be inserted.

2. Using this method, it is not necessary to connect the source

coil feedback voltage RF cable between the source coil and

the source board.

3. Make sure the entire system is fully assembled prior to making

electrical connections.

4. With power o , connect the main input power supply bus to

(J62). Note the polarity of the supply connector.

5. With power o , connect the gate drive input signals to (J10,

Pin-1 = Low-side, Pin-2=Ground, Pin-3=High-side) and activate

signals. Make sure the gating signal are within speci cations.

6. With power o , connect the control input power supply bus

to +V

(J90). Note the polarity of the supply connector.

7. Set the load to the desired value (see table for setting jump-

ers or use an appropriate external load).

8. Turn on the control supply – make sure the supply is between

7 V and 12 V range (8.5 V is recommended).

9. Turn on the main supply voltage starting at 0 V and increase

slowly to the required value (do not exceed the absolute

maximum voltage of 24 V on V

operates.

10. Once operational, adjust the main supply voltage and oscil-

lator frequency within the operating range and observe the

output switching behavior, e ciency and other parameters.

11. For shutdown, please follow steps in the reverse order. Start

by reducing the main supply voltage to 0 V followed by steps

8 through 4.

NOTE. 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 mea-

surement of the Source Coil Voltage (SJ41) and the Device Coil Voltage (SJ81) that

is compatible with 5 mm Tektronix probes.

Alternatively, by removing the heat-sink, the Source Coil Voltage can be mea-

sured by placing the oscilloscope probe tip through the large via on the switch-

node (J46 - designed for this purpose) and grounding the probe directly across

the GND post (J44 - must be installed). See Figure 7 for proper scope probe tech-

nique. Using this technique will signi cantly limit the operating power as the FETs

and gate driver IC will heat up signi cantly and care must be taken not to exceed

the junction temperature of the eGaN FETs.

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). Observe that the system

OUT