SKHI24 Datasheet, PDF (5/8 Pages) Semikron International – Hybrid Dual IGBT Driver

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.
Technical explanations¹
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.
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.
© by SEMIKRON 22-08-2003
Driver Electronic – PCB Drivers 1919