AN2123 STMICROELECTRONICS | Alldatasheet
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Technical content
1 Introduction
ratings of 15 to 75 A in Econopak-like modules (see Figure 2).
- input stage compatible with both an optocoupler and a pulse transformer.
Figure 1. TD351 in 3-phase inverter application (1200 V IGBTs)
2 TD351 application example
in parallel with a bigger electrolytic capacitor. Figure 2. IGBT modules Figure 3. TD351 application example
3 Input stage
in Figure 4 can be considered as example of use with both solutions. Figure 5). To turn TD351 output on, the input signal must be lower than 0.8 V for 220 ns minimum. the IN pin must be between 0 and 5 V. Figure 4. Application schematic (pulse transformer at left; optocoupler at right) Figure 5. Typical input signal waveforms with pulse transformer (left) or optocoupler (right)
4 Output stage
IGBT driving, and the IGBT gate resistor should not be lower than about 15 Ω. Figure 6. Typical Output stage current capability at 25°C (VH=16V) Figure 7. Typical VOL and VOH voltage variation with temperature
5 Active Miller clamp
The TD351 offers an alternative solution to the problem of Miller current in IGBT switching applications. characteristics, but simply keeps the gate at a low level during the entire off-time. bootstrap technique for the high-side driver supply, and a consistent cost reduction for the application. the driver to control turn-on and turn-off. the voltage spike on IGBT gate. capacitor to control the voltage spike on gate. Figure 8. Active Miller Clamp: principles of operation
capacitors and with the active Miller clamp. shows a schematic principle with external buffers for both the driver output and the clamp function. Figure 9. Active Miller clamp: test waveforms related to above schematic Figure 10. Using external buffer to increase the current capability of the driver and clamp outputs
5 CLAMP
from the CLAMP output as an secondary gate discharge path (see Figure 11 below). when the IGBT is in the OFF state without affecting the IGBT turn-off characteristics. Figure 11. High power application: negative gate drive and secondary gate discharge path
slight increase to conduction losses). enabled again to end the turn-off sequence. value than the 2-level turn-off delay (see Figure 13). delay from about 0.7 to 6.6 microseconds. Figure 12. Principle schematic for 2-level turn-off feature
7 Application schematic
shows the half bridge design concept using the TD35x. special action from the system controller. sink) and the IGBT gate resistor. the turn-on and turn-off behavior, especially regarding switching losses and EMI issues. application power is indicated. Figure 16. TD35x application concept
the theoretical 0.8 A or 0.9 A peak values; this usually doesn’t affect the application performance. An external buffer will be required for higher power applications. A reference schematic is shown in Figure 17. It uses a bootstrap principle for the high-side driver supply. referenced to the ground level. Table 1. Recommended gate resistors
Figure 17. TD351 Application Schematic with 2-Level Turn-off
8 Conclusion
The TD351 is part of the new TD35x IGBT driver family, and is designed for 1200 V, 3-phase inverter applications, especially for motor control and UPS systems. It covers a large range of power applications, from 0.5 kW to more than 100 kW. Thanks to its Ac tive Miller Clamp feature and low quiescent current, it can help avoid using negative gate driving for application up to 10 kW and simplifies the global power supply system for cost-sensitive applications.
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the co nsequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publicati on are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics prod ucts are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectro nics. The ST logo is a registered trademark of STMicroelectronics All other names are the property of their respective owners © 2005 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Repubic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America
9 Revision history
Date Revision Description of changes 01 Feb. 2005 1 First release.