NOVOSENSE NSIP3266: Full-Bridge Transformer Driver for Isolated Power Supply Applications

Introduction: Solving Isolated Driver Power Supply Challenges

In modern high-voltage power systems—from automotive on-board chargers (OBCs) to industrial energy storage and server power supplies—isolated driver power supplies are essential for safety and performance. However, engineers often face complex design challenges when implementing these circuits, balancing cost, complexity, and reliability. NOVOSENSE addresses these challenges with the NSIP3266, a full-bridge transformer driver with integrated crystal oscillator, comprehensive protection features, and ingenious design that significantly simplifies isolated driver power supply implementation.

The NSIP3266 supports full-bridge topology with a wide input range, offering engineers a streamlined solution that reduces component count, simplifies layout, and accelerates time-to-market for critical power applications. This article explores how this innovative device addresses common isolated power supply challenges and provides a more efficient path to reliable system design.

Understanding Isolated Power Architectures: Centralised vs. Distributed

Before diving into the NSIP3266's capabilities, it's important to understand the architectural approaches for isolated driver power supplies in high-voltage systems, which typically fall into three categories:

Centralised Architecture

In a centralised approach, a single power supply stage delivers power to multiple loads. While seemingly simple, this architecture presents significant challenges:

• Wide input voltage range requiring closed-loop regulation

• Complex transformer design with multiple secondary windings

• Multi-output load regulation issues

• Long wiring increasing parasitic effects and design complexity

Fully Distributed Architecture

At the opposite end of the spectrum, fully distributed systems use independent isolated power modules for each driver:

• Provides targeted 1-to-1 power delivery and protection

• Enables modular design and simplified maintenance

• Significantly increases system cost due to multiple isolated power modules

• Results in component redundancy and larger footprint

Semi-Distributed Architecture

The semi-distributed approach offers a balanced solution:

• Two-stage auxiliary power design with regulated first stage and open-loop second stage

• Simplified design compared to centralised architecture

• Better cost-performance balance than fully distributed systems

• Enhanced protection capabilities with reasonable component count

The NSIP3266 is specifically designed for this semi-distributed architecture, addressing the need for a reliable, cost-effective solution that maintains system integrity while reducing design complexity.

NSIP3266: Full-Bridge Topology for Simplified Design

NOVOSENSE's NSIP3266 adopts a full-bridge topology that provides significant advantages over alternative approaches like push-pull or LLC:

Key Benefits of Full-Bridge Topology

• Simplified Transformer Design: Doesn't require center-tapped transformers

• Minimal External Components: Reduced BOM compared to LLC resonant converters

• Design Tolerance: Better handling of transformer parasitics and leakage inductance

• Implementation Flexibility: Works effectively across various power levels

The full-bridge configuration (H-bridge) provides a straightforward voltage conversion ratio where the output-to-input voltage ratio equals the transformer turns ratio (Vout/Vin = D/n), making power supply design more predictable and stable.

Innovative Features Freeing MCU Resources

One of the NSIP3266's most valuable innovations is how it reduces dependency on MCU control, saving valuable system resources:

Integrated Crystal Oscillator

The internal oscillator circuit eliminates the need for MCU-based PWM generation, allowing frequency configuration with just a simple external resistor on the RT pin. This provides:

• Decoupled MCU control for more flexible PCB layout

• Continued safe operation even during MCU failure

• Simplified development with fewer firmware requirements

Built-in Soft Start

The NSIP3266 integrates soft-start functionality that:

• Eliminates the need for MCU-controlled start-up sequences

• Prevents inrush current issues during system initialisation

• Reduces stress on transformer and output components

Secondary-Side Optimisation

By eliminating the need for secondary-side current limiting resistors, the NSIP3266:

• Simplifies board design with fewer components

• Reduces power losses for better efficiency

• Improves flexibility in architectural implementation

Wide Input Range and Comprehensive Protection

The NSIP3266 supports a wide 6.5V to 26V operating voltage range, making it versatile for various automotive and industrial applications. This broad range:

• Eliminates the need for additional TVS protection devices

• Provides flexibility in choosing pre-stage power supply

• Simplifies inventory management with a single part supporting multiple applications

Integrated Protection Features

Critical for reliable operation in demanding environments, the NSIP3266 includes:

• Undervoltage protection (UVLO)

• Overcurrent protection (OCP)

• Over-temperature protection (OTP)

• Fault reporting through dedicated FAULT pin

These protection features enable engineers to focus on optimising core system functionality while ensuring reliable operation in demanding environments like automotive and industrial systems.

Technical Specifications and Packaging

The NSIP3266 comes in a compact EP-MSOP8 package (3.0 x 3.0mm x 0.65mm with thermal pad), optimising PCB space while providing sufficient thermal performance. Two versions will be available in the first half of 2025:

• NSIP3266-D: Industrial version for general-purpose applications

• NSIP3266-Q1: Automotive-qualified version meeting AEC-Q100 requirements

Applications Across Multiple Industries

The NSIP3266 is well-suited for isolated driver power supply circuits in:

Automotive Applications

• On-board chargers (OBCs)

• Traction inverters

• Electric vehicle charging infrastructure

Industrial Applications

• Photovoltaic power generation systems

• Energy storage solutions

• Industrial motor drives

• Factory automation equipment

Server and Telecom

• Server power supplies

• Telecom power systems

• Data center backup power

Part of a Comprehensive Isolation Portfolio

The NSIP3266 is one component in NOVOSENSE's broader "isolation+" product portfolio that includes:

• NSIP605x Series: Push-pull transformer drivers

• NSIP88/89xx and NIRSP31x Series: Integrated transformers with multi-channel digital isolators

• NSIP83086: Isolated RS485 transceiver

• NSIP1042: Isolated CAN transceiver

This comprehensive range allows engineers to source multiple isolation components from a single supplier, simplifying procurement and ensuring compatibility.

Conclusion: Simplifying Isolated Power Design with the NSIP3266 full bridge transformer driver

The NOVOSENSE NSIP3266 full-bridge transformer driver addresses key challenges in designing isolated driver power supplies for high-voltage systems. With its integrated crystal oscillator, comprehensive protection features, and clever pin configuration, it significantly reduces design complexity while enhancing reliability.

By supporting the semi-distributed power architecture approach, the NSIP3266 provides an ideal balance of performance, protection, and cost-effectiveness. Whether for automotive, industrial, or server applications, this innovative component streamlines isolated power design, accelerating time-to-market while ensuring robust operation in demanding environments.

For engineers struggling with isolated driver power supply design complexities, the NSIP3266 offers a simplified path forward with fewer components, reduced MCU dependencies, and enhanced protection capabilities in a compact package. Contact Ineltek for pricing, lead time and samples.