Knowles, Cornell Dubilier brand, has introduced the Type PPH series of double‑metallized polypropylene film capacitors for high‑voltage, high‑stress automotive and industrial power electronics.
These Knowles film capacitors target snubber, commutation and pulse applications where switching devices face high dv/dt, ripple current and demanding environmental conditions.
Key features and benefits
- Double‑metallized polypropylene film construction for stable capacitance, low dielectric losses and good pulse endurance in demanding power circuits.
- Epoxy‑encapsulated plastic box package with tinned copper leads, providing mechanical robustness and reliable PCB mounting in automotive and industrial assemblies.
- Capacitance range from approximately 0.001 µF to 4.7 µF, supporting use from very fast, low‑energy snubbers up to higher‑energy pulse and commutation networks.
- Voltage ratings up to 2000 VDC, making the series suitable for high‑voltage DC links, snubbers in traction inverters, and protection around SiC and IGBT modules.
- Wide operating temperature range from −55 °C to +105 °C, allowing use in under‑hood automotive, industrial cabinet and outdoor power installations.
- High ripple current capability, supporting continuous operation in high‑frequency switching converters and pulse circuits without excessive self‑heating.
- Self‑healing dielectric, where local breakdowns of the metallized film tend to clear without catastrophic failure, improving long‑term reliability.
- Low loss and minimal inherent temperature rise, helping engineers to meet efficiency and thermal design targets in compact power converter layouts.
- AEC‑Q200 qualification, aligning the series with automotive‑grade requirements including extended temperature and humidity testing.
Typical applications
Type PPH capacitors are intended for power electronics circuits where switching devices are repeatedly exposed to high voltage transients. They are used to shape voltage and current waveforms, absorb spikes and limit dv/dt seen by semiconductor devices.
Power switching and protection
- Snubber networks across IGBTs, MOSFETs and rectifiers in hard‑switched converters and inverters.
- Commutation circuits in SCR‑based power controls, including industrial drives and soft‑start units.
- Protection of IGBT and SiC MOSFET modules in traction, industrial and renewable energy inverters.
Automotive and transportation
- Automotive powertrains and onboard electronics where high‑voltage switching is used for motor control and DC‑DC conversion.
- EV charging systems, including on‑board chargers and external DC fast chargers with high‑voltage stages.
- Auxiliary converters and power distribution units in electrified vehicles requiring automotive‑qualified passive components.
Industrial and energy
- Industrial power supplies and inverters for motion control, robotics and process automation.
- Renewable and alternative energy systems such as PV string inverters and battery energy storage converters.
- High‑frequency switching circuits where repetitive pulses and high dv/dt must be controlled to protect semiconductors.
Technical highlights
The Type PPH series combines a specific film construction with a protected box housing and radial leads aimed at both electrical performance and mechanical reliability.
Construction and materials
- Double‑sided metallized polypropylene film as the dielectric and electrode system, optimized for low losses and self‑healing behavior.
- Epoxy resin encapsulation in a plastic box, shielding the element from humidity and contaminants while improving mechanical stability.
- Two tinned copper wire leads suitable for through‑hole mounting and soldering into standard power electronics assemblies.
Electrical and environmental performance
- Capacitance values roughly spanning 0.001 µF to 4.7 µF according to the manufacturer datasheet, covering typical snubber and pulse energy requirements.
- Voltage ratings up to 2000 VDC, enabling use on high‑voltage rails and across switching devices in traction and industrial inverters.
- Operating temperature range of −55 °C to +105 °C, supporting designs with wide ambient and internal temperature variations.
- Performance validated under high temperature and humidity conditions (85 °C / 85% RH for 2,000 hours) in line with AEC‑Q200 testing.
Summary table of key parameters
| Parameter | Typical Type PPH characteristic |
|---|---|
| Dielectric | Polypropylene film, double‑metallized |
| Capacitance range | Approx. 0.001 µF to 4.7 µF (per manufacturer datasheet) |
| Maximum voltage rating | Up to 2000 VDC |
| Operating temperature range | −55 °C to +105 °C |
| Qualification | AEC‑Q200 |
| Package style | Epoxy‑encapsulated plastic box, radial tinned copper leads |
Values and ranges should be confirmed against the latest manufacturer datasheet for the specific part number selected.
Design‑in notes for engineers
When designing snubber and commutation networks, engineers must balance energy handling, dv/dt, thermal behavior and mechanical integration. The Type PPH series provides a standardized platform for these tasks in automotive and industrial contexts.
- Verify energy per pulse and average power dissipation in the snubber or pulse circuit, and select a PPH value whose capacitance and voltage rating can safely absorb the expected transients according to the datasheet.
- Check peak dv/dt and ripple current against the series capabilities to avoid excessive self‑heating, especially in high‑frequency converters and SiC‑based designs where edge rates are very high.
- Use the self‑healing behavior of metallized polypropylene as an advantage, but still design for appropriate margins in voltage and temperature to maximize service life in harsh environments.
- Pay attention to creepage, clearance and lead spacing when placing PPH capacitors near high‑voltage nodes, ensuring that PCB layout and case dimensions meet system‑level insulation requirements.
- Consider the AEC‑Q200 qualification when selecting parts for automotive projects, noting that this helps align with OEM and Tier‑1 qualification expectations.
- Review humidity and temperature derating curves from the datasheet, especially for applications near the upper temperature limit or in high‑humidity locations such as under‑hood or outdoor enclosures.
- Plan for mechanical support in environments subject to vibration and shock, using the box package and radial leads in combination with appropriate PCB mounting and, if necessary, additional mechanical fixation.
For high‑frequency and high‑voltage systems using SiC MOSFETs or fast IGBTs, careful snubber design with suitable film capacitors like the PPH series can significantly reduce switching losses and improve device reliability.
Source
This article is based on information provided in Knowles’ press release introducing the Cornell Dubilier Type PPH capacitor series and the associated PPH series datasheet.
