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PDF SI8284 Data sheet ( Hoja de datos )
| Número de pieza | SI8284 | |
| Descripción | 4.0 Amp ISODrivers | |
| Fabricantes | Silicon Laboratories | |
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Si8281/82/83/84 Data Sheet
4.0 Amp ISODrivers with Integrated DC-DC Converters
The Si828x family (Si8281/82/83/84) is made up of isolated, high-current gate drivers
with integrated system safety and feedback functions. These devices are ideal for driving
power MOSFETs and IGBTs used in a wide variety of inverter and motor control applica-
tions. The Si828x isolated gate drivers utilize Silicon Labs' proprietary silicon isolation
technology, supporting up to 5.0 kVrms withstand voltage per UL1577. This technology
enables higher-performance, reduced variation with temperature and age, tighter part-to-
part matching, and superior common-mode rejection compared to other isolated gate
driver technologies.
In addition to the gate driver, the Si828x family integrates a dc-dc controller for simple
implementation of an isolated supply for the driver side. The Si828x dc-dc controller can
be ordered in two different configurations depending on what system voltage rails are
available and the amount of power needed. The Si8281 and Si8283 have integrated
power switch but are limited in dc-dc voltage input to the device bias. The Si8282 and
Si8284 utilize and external power switch and are able to accept much higher voltage in-
put power rail. User-adjustable frequency for minimizing emissions, a soft-start function
for safety, and a shut-down option are available options. The device requires only mini-
mal passive components and a miniature transformer.
The input to the device is a complementary digital input that can be utilized in several
configurations. The input side of the isolation also has several control and feedback digi-
tal signals. The controller to the device receives information about the driver side power
state and fault state of the device and recovers the device from fault through an active-
low reset pin.
On the output side, Si828x devices provide separate pull-up and pull-down pins for the
gate. A dedicated DSAT pin detects the desaturation condition and immediately shuts
down the driver in a controlled manner. The Si828x devices also integrate a Miller clamp
to facilitate a strong turn-off of the power switch.
Applications
• IGBT/ MOSFET gate drives
• Industrial, HEV, and renewable energy inverters
• AC, Brushless, and DC motor controls and drives
• Variable-speed motor controllers
• Isolated switch mode and UPS power supplies
Safety Regulatory Approvals (Pending)
• UL 1577 recognized
• Up to 5000 VRMS for 1 minute
• CSA component notice 5A approval
• IEC 60950-1, 61010-1, 60601-1 (reinforced insulation)
• VDE certification conformity
• IEC 60747-5-5/VDE0884 Part 10
• CQC certification approval
• GB4943.1
KEY FEATURES
• 4 A IGBT driver
• System Safety Features
• DESAT detection
• FAULT feedback
• Undervoltage Lock Out (UVLO)
• Soft shutdown on fault condition
• Silicon Labs’ high-performance isolation
technology
• Industry leading noise immunity
• High speed, low latency and skew
• Best reliability available
• 30 V driver-side supply voltage
• Integrated Miller clamp
• Power ready pin
• Complementary driver control input
• Compact packages: 20 and 24-pin wide-
body SOIC
• Integrated DC-DC converter
• Feedback-controlled converter with
dithering for low EMI
• DC-DC converter efficiency of 83%
• Shutdown, frequency, and soft-start
controls
• Industrial temp range: –40 to 125 °C
silabs.com | Smart. Connected. Energy-friendly.
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Preliminary Rev. 0.5
1 page  
Si8281/82/83/84 Data Sheet
System Overview
2.9 Desaturation Detection
The Si828x provides sufficient voltage and current to drive and keep the IGBT in saturation during on time to minimize power dissipa-
tion and maintain high efficiency operation. However, abnormal load conditions can force the IGBT out of saturation and cause perma-
nent damage to the IGBT.
To protect the IGBT during abnormal load conditions, the Si828x detects an IGBT desaturation condition, shuts down the driver upon
detecting a fault, and provides a fault indication to the controller. These integrated features provide desaturation protection with mini-
mum external BOM cost. The figure below illustrates the Si828x desaturation circuit. When the Si828x driver output is high, the internal
current source is on, and this current flows from the DSAT pin to charge the CBL capacitor. The voltage on the DSAT pin is monitored
by an internal comparator. Since the DSAT pin is connected to the IGBT collector through the DDSAT and a small RDSAT, its voltage is
almost the same as the VCE of the IGBT. If the VCE of the IGBT does not drop below the Si828x desaturation threshold voltage within a
certain time after turning on the IGBT (blanking period) the block will generate a fault signal. The Si828x desaturation hysteresis is fixed
at 220 mV and threshold is nominally 7 V.
Driver Control Signal
Ich
g
Fault Signal DESAT Sense
Driver Disable
7V
DSAT
DDSAT
RDSAT
CBL
VMID
Figure 2.3. Desaturation Circuit
As an additional feature, the block supports a blanking timer function to mask the turn-on transient of the external switching device and
avoid unexpected fault signal generation. This function requires an external blanking capacitor, CBL, of typically 390 pF between DSAT
and VMID pins. The block includes a 1 mA current source (IChg) to charge the CBL. This current source, the value of the external CBL,
and the programmed fault threshold, determine the blanking time (tBlanking).
tBlanking = CBL
×
V DESAT
Ichg
An internal nmos switch is implemented between DSAT and VMID to discharge the external blanking capacitor, CBL, and reset the
blanking timer. The current limiting RDSAT resistor protects the DSAT pin from large current flow toward the IGBT collector during the
IGBT’s body diode freewheeling period (with possible large collector’s negative voltage, relative to IGBT’s emitter).
2.10 Soft Shutdown
To avoid excessive dV/dt on the IGBT’s collector during fault shut down, the Si828x implements a soft shut down feature to discharge
the IGBT’s gate slowly. When soft shut down is activated, the high power driver goes inactive, and a weak pull down via VH and exter-
nal RH discharges the gate until the gate voltage level is reduced to the VSSB + 2 V level. The high power driver is then turned on to
clamp the IGBT gate voltage to VMID.
After the soft shut down, the Si828x driver output voltage is clamped low to keep the IGBT in the off state.
silabs.com | Smart. Connected. Energy-friendly.
Preliminary Rev. 0.5 | 4
5 Page 
Si8281/82/83/84 Data Sheet
System Overview
2.13 Transformer Design
The internal switch dc-dc (Si8281, Si8283) and external switch dc-dc (Si8282, Si8284) operate in different topologies and, thus, require
different transformer designs. The table below provides a list of transformers and their parametric characteristics that have been valida-
ted to work with Si828x products. It is recommended that users order the transformers from the vendors per the part numbers given
below.
To manufacture transformers from your preferred suppliers that may not be listed below, please specify to supplier the parametric char-
acteristics as specified in the table below for a given input voltage and isolation rating.
Table 2.2. Si828x Recommended Transformers
Transformer Supplier
UMEC
www.umec-usa.com
Coilcraft
www.coilcraft.com
Ordering Part #
UTB02257s
UTB02241s
UTB02253s
TA7788-AL
Input Turns Ratio Leakage
Primary
Primary
Voltage
Inductance Inductance Resistance
3.0–5.5 V 1:15:5 125 nH max 1.5 µH ± 5% 0.05 Ω max
4.5–5.5 V 1:9:33.667 100 nH max 2 µH ± 5% 0.05 Ω max
7–24 V
1.2:1.21 200 nH max 25 µH ± 5% 0.225 Ω max
7–24 V 1:1.25:0.75 550 nH max 25 µH ± 5% 0.460 Ω max
Isolation
Rating
5 kV
5 kV
5 kV
5 kV
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Preliminary Rev. 0.5 | 10
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet SI8284.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| SI8281 | 4.0 Amp ISODrivers | Silicon Laboratories |
| SI8282 | 4.0 Amp ISODrivers | Silicon Laboratories |
| SI8283 | 4.0 Amp ISODrivers | Silicon Laboratories |
| SI8284 | 4.0 Amp ISODrivers | Silicon Laboratories |
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