SKHI 24 ...
External Components
Component
R
CE
Function
Reference voltage for V
CE
-monitoring
10
⋅
R
CE
(
kΩ
)
-
V
CEstat
(
V
)
= ----------------------------------- – 1,4
10 + R
CE
(
kΩ
)
with R
VCE
= 1kΩ (1700V IGBT):
10
⋅
R
CE
(
kΩ
)
-
V
CEstat
(
V
)
= ----------------------------------- – 1,8
10 + R
CE
(
kΩ
)
(1)
Recommended Value
10kΩ < R
CE
< 100kΩ
18kΩ for SKM XX 123 (1200V)
36kΩ for SKM XX 173 (1700V)
(1.1)
C
CE
< 2,7nF
(2)
0,33nF for SKM XX 123 (1200V)
0,47nF for SKM XX 173 (1700V)
0,5µs < t
min
< 10µs
(3)
C
CE
Inhibit time for V
CE
- monitoring
15 – V
CEstat
(
V
)
-
t
min
=
τ
CE
⋅
ln ---------------------------------------
10 – V
CEstat
(
V
)
10
⋅
R
CE
(
kΩ
)
-
τ
CE
( µs )
= C
CE
(
nF
) ⋅
-----------------------------------
10 + R
CE
(
kΩ
)
R
VCE
R
ERROR
Collector series resistance for 1700V
IGBT-operation
Pull-up resistance at error output
U
Pull – Up
-----------------------
<
15mA
R
ERROR
1kΩ / 0,4W
1kΩ < R
ERROR
< 10kΩ
R
GON
R
GOFF
3)
4)
Turn-on speed of the IGBT
3)
Turn-off speed of the IGBT
4)
R
GON
> 1,5Ω
R
GOFF
> 1,5Ω
Higher resistance reduces free-wheeling diode peak recovery current, increases IGBT turn-on time.
Higher resistance reduces turn-off peak voltage, increases turn-off time and turn-off power dissipation
1916
Driver Electronic – PCB Drivers
10-06-2008
© by SEMIKRON
SKHI 24 ...
PIN array
Fig. 6 shows the pin arrays. The input side (primary side) comprises 10 inputs, forming the interface to the control circuit
(see fig.1).
The output side (secondary side) of the hybrid driver shows two symmetrical groups of pins with 5 outputs, each forming
the interface to the power module. All pins are designed for a grid of 2,54 mm in two rows.
Primary side PIN array
PIN No. Designation
P1
P2
P3
P4, P5,
P6, P7
P8
P9, P10
P13
P14
Shield
V
IN2
V
IN1
free
/ERROR
GND/0V
TDT1
TDT2
Explanation
internally connected to GND
switching signal input 2 (BOTTOM switch); positive 5V logic
switching signal input 1 (TOP switch); positive 5V logic
not wired
error output, low = error; open collector output; max 30V / 15mA
ground
+ 15V ± 4% voltage supply
signal input for digital adjustment of locking time; to be switched by
bridge to GND
signal input for digital adjustment of locking time; to be switched by
bridge to GND
signal input for inhibiting locking function; to be connected by bridge
to GND
not wired
P11, P12 V
S
P15
SELECT
P16, P17,
P18, P19, free
P20
ATTENTION:
The contactor tracks of the digital input signals P13/ P14/ P15 must not be longer than 20 mm to avoid
interferences, if no bridges are connected.
Secondary side PIN array
PIN No. Designation Explanation
ST1
ST2
ST3
ST4
ST9
SB1
SB2
SB3
SB4
SB9
G
OFF1
G
ON1
E1
C
CE1
V
CE1
G
OFF2
G
ON2
E2
C
CE2
V
CE2
gate 1 R
OFF
output (TOP switch)
gate 1 R
ON
output (TOP switch)
emitter output IGBT 1 (TOP switch)
reference voltage adjustment with R
CE
and C
CE
(TOP switch)
collector output IGBT 1 (TOP switch)
gate 2 R
OFF
output (BOTTOM switch)
gate 2 R
ON
output (BOTTOM switch)
emitter output IGBT 2 (BOTTOM switch)
reference voltage adjustment with R
CE
and C
CE
(BOTTOM switch)
collector output IGBT 2 (BOTTOM switch)
ATTENTION:
The connector leads to the power module should be as short as possible.
© by SEMIKRON 10-06-2008
Driver Electronic – PCB Drivers
1917
SKHI 24 ...
SEMIDRIVER
TM
SKHI 24
Hybrid dual drivers
The driver generation SKHI 24 is supplementing the
SKHI 21/22 and is suitable for all available medium and
high power range IGBT and MOSFETs. It can be said that
the SKHI 24 is a function-compatible further developed
SKHI 22B. It is recommended to use the SKHI 24 for any
new design.
General description
The new driver generation SKHI 22A/B, SKHI 21A and
also SKHI 24 are hybrid components which may directly
be mounted to the PCB.
All devices necessary for driving, voltage supply, error
monitoring and potential separation are integrated in the
driver. In order to adapt the driver to the used power
module, only very few additional wiring will be necessary.
The forward voltage of the IGBT is detected by an
integrated short-circuit protection, which will turn off the
module when a certain threshold is exceeded.
In case of short-circuit or too low supply voltage the
integrated error memory is set and an error signal is
generated.
The driver is connected to a controlled + 15 V-supply
voltage. The input signal level is 0/5 V.
P15 ;
SELECT
open / 5V
open / 5V
open / 5V
open / 5V
GND
P13 ;
TDT1
GND
GND
open / 5V
open / 5V
X
P14 ;
TDT2
GND
open / 5V
GND
open / 5V
X
interlock time
t
TD
/µs
1,3
2,3
3,3
4,3
no interlock
Fig. 2 SKHI 24 - Selection of interlock-times: "High"-level
can be achieved by no connection or connecting to
5 V.
Short pulse suppression
The integrated short pulse suppression avoids very short
switching pulses at the power semiconductor caused by
high-frequency interference pulses at the driver input
signals. Switching pulses shorter than 500ns are
suppressed and not transmitted to the IGBT.
Power supply monitoring (V
S
)
A controlled 15 V-supply voltage is applied to the driver. If
it falls below 13 V, an error is monitored and the error
output signal switches to low level.
Error monitoring and error memory
The error memory is set in case of under-voltage or
short-circuit of the IGBTs. In case of short-circuit, an error
signal is transmitted by the V
CE
-input via the pulse
transformers to the error memory. The error memory will
lock all switching pulses to the IGBTs and trigger the error
output (P8) of the driver. The error output consists of an
open collector transistor, which directs the signal to earth
in case of error. SEMIKRON recommends the user to
provide for a pull-up resistor directly connected to the error
evaluation board and to adapt the error level to the desired
signal voltage this way. The open collector transistor may
be connected to max. 30 V / 15 mA. If several SKHI 24 are
used in one device, the error terminals may also be
paralleled.
The error memory may only be reset, if no error is pending
and both cycle signal inputs are set to low for > 12 µs at
the same time.
Pulse transformer set
The transformer set consists of two pulse transformers.
One of them is used bidirectional for turn-on and turn-off
signals of the IGBT and the error feedback between
primary and secondary side, the other one for the DC/
DC-converter. The DC/DC-converter serves as
potential-separation and power supply for the two
secondary sides of the driver. The isolation voltage is
4000 VAC .
The secondary side consists of two sym-metrical
driver switches integrating the following components:
Supply voltage
The voltage supply consists of a rectifier, a capacitor, a
voltage controller for – 8 V and + 15 V and a + 10 V
reference voltage.
Driver Electronic – PCB Drivers
1919
Technical explanations
1
Description of the circuit block diagram and the
functions of the driver
The block diagram (fig.1) shows the inputs of the driver
(primary side) on the left side and the outputs (secondary
side) on the right.
The following functions are allocated to the primary
side:
Input-Schmitt-trigger,
positive logic (input high = IGBT
on). It is also possible to drive the circuit input with 15 V
logic, but a 6.8 kΩ resistor has to be connected in series
with the input pin (and the internal 100
Ω
resistor).
Interlock circuit and deadtime generation of the IGBT
If one IGBT is turned on, the other IGBT of a halfbridge
cannot be switched. Additionally, a digitally adjustable
interlocking time is generated by the driver (see fig. 2),
which has to be longer than the turn-off delay time of the
IGBT. This is to avoid that one IGBT is turned on before
the other one is not completely discharged. This
protection-function may be neutralized by switching the
select input (pin15) (see fig. 2). fig. 2 documents possible
interlock-times. „High“ value can be achieved with no
connection and connection to 5 V as well.
1. The following descriptions apply to the use of the hybrid driver
for IGBTs as well as for power MOSFETs. For the reason of
shortness, only IGBTs will be mentioned in the following. The
designations „collector“ and „emitter“ will refer to IGBTs,
whereas for the MOSFETs „drain“ and „source“ are to be read
instead.
© by SEMIKRON 10-06-2008
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