Rohm TO-247-4L, Руководство по эксплуатации

Страница: 8 / 42

5/38
TO-247-4L Half-Bridge Evaluation Board
User’s Guide
©
2019 ROHM Co., Ltd.
No. 61UG047E Rev.001
August.2019
OCP circuit configuration consists of transistors for start-up (Q301, Q305), transistor for Latch (Q303), transistor for Gate OFF
(Q304), and transistor for LED indication (Q306). Furthermore, the resistors R362/R363 and R364/R365 to select the OCP circuit
GND are available. Table 4 shows the relation between the bias voltage and mounted resistors. Default setting is Zero bias.
Table 3. Level-shifting Resistor Adjustment
Table 4. OCP GND Setting Based on Bias Voltage
In addition, to minimize the time taken from OCP circuit start-up until LS MOSFET turns OFF, the driver IC (U102) SCPIN voltage
will be directly set high using the Gate OFF signal, MOSFET Gate signal can be cut off within 1us after the start-up of the SCP.
However, when OCP circuit operates, the OCP Latch circuit will operate. OCP condition continues and turns ON the LED302 (red)
even though the MOSFET Gate signal has been cut off. After the cause of the OCP occurrence is cleared, the Latch circuit can be
reset by pushing the Reset switch (SW301).
Location of the OCP Reset switch and the resistors for the adjustment are shown in Figure 4.
Bias Voltage R341
R342 R359 R353 R361 Remarks
Zero bias
4.7k
220 470 100 470 No OCP Adjustment
-2V
220 2.2k 100 Not
mounted
Adjust at RV301
-3.0V
470 3.3k 56
-3.6V
220 4.7k 47
-4.0V
220 5.6k 39
Bias Voltage R362
R363 R364 R365
Zero bias
0Ω 0Ω
Not mounted Not mounted
Negative bias
Not
mounted
Not mounted
0Ω 0Ω