CS8312 Cherry Semiconductor Corporation, CS8312 Datasheet - Page 3

• Manufacturer Part Number: CS8312
• Description: IGBT Ignition Predriver with Dynamic Current Regulation
• Manufacturer: Cherry Semiconductor Corporation

The flag indicates when the voltage across the two sense
pins is approaching a current limit level that has been
determined by the value of the external sense resistor
(R
voltage across the sense pins (SENSE+, SENSE-) is less
than the flag turn-on voltage, then the FLAG is off. When
the voltage between the sense pins equals the FLAG turn
on voltage, the FLAG will latch on until the CTRL pin
goes low. FLAG is disabled whenever CTRL is low.
Changing the CLI pin from low to high will increase
nominal FLAG turn on voltage by approximately 45%.
Table 1 FLAG Timing Sequence
SENSE
Flag Function: continued
Turn Off Delay
Turn On Delay
Disable Time
Sense Function
Input Voltage Range
Sense Regulation Voltage
Input Leakage Current
Propagation Delay
State
0
1
2
3
0
) and the state of the CTRL and CLI pins. If the
PARAMETER
PACKAGE PIN #
Flag Function (see Application Diagram)
8L PDIP & SO
CONTROL
High
High
High
Low
Low
1
2
3
4
5
6
7
8
Above Threshold
Below Threshold
SENSE+
X
X
X
CTRL decreasing
V
V
V
V
CTRL
CTRL
CTRL
CTRL
PIN SYMBOL
FLAG
SENSE+
SENSEÐ
Gnd
OUT
CLI
CTRL
V
TEST CONDITIONS
CC
=5.5V; V
=5.5V; V
=5.5V
=5.5V
Electrical Characteristics continued
Package Pin Description
FLAG
OFF
OFF
OFF
ON
ON
Circuit Description
CLI
CLI
=-0.3V
=5.5V
Indicates whether current through the IGBT has reached a pre-
set level.
Positive input to current comparator.
Ground (SENSE-) for current sense resistor.
Ground connection.
Output voltage to IGBT (MOSFET) gate.
Current limit input increase.
Control input.
Supply voltage.
3
The CS8312 output (OUT) saturates and supplies voltage
to the IGBT (or MOSFET) gate once the CTRL switches
from low to high. As current through the IGBT (MOSFET)
increases and the voltage across the sense resistor passes
the flag turn on voltage, the FLAG will turn on. If the cur-
rent through the sense resistor continues to rise and the
sense resistor voltage reaches the regulation sense volt-
age, then the gate voltage will fall to a level that regulates
the driver and maintains the regulation sense voltage at
the sense resistor.
Changing the CLI pin from a logic low to a logic high
increases the FLAG turn on voltage by approximately
45% and the regulation sense voltage by approximately
39% respectively.
MIN
100
-0.3
270
380
Current Limit Function
FUNCTION
Output Stage
TYP
295
410
MAX
10
10
450
2.5
320
440
5
20
UNIT
us
us
us
V
mV
mV
µA
us