Datasheet TDA51S-41HC (Mornsun) - 7

Figure 9. CMTI Test Circuit Note: 1. The High Voltage Surge Generator generates repetitive high voltage surges with > 1.5kV amplitude and <10ns rise time and fal time to reach common-mode transient noise with > 150kV/μs slew rate. 2. CL is the load capacitance about 15pF together with the instrumentation capacitance. 3. Pass-fail criteria: The output must remain stable whenever the high voltage surges come. 4. CBP is the 0.1 to 1uF bypass capacitance. Detailed Description TDA51S-41HC has a high-efficiency, low-emissions isolated dc-dc converter, with high-speed isolated data channels. The dc-to-dc converter section of the TDA51S-41HC devices works on principles that are common to most modern power supplies.The devices have a split control er architecture with isolated PWM feedback. VCC power is supplied to an oscil ating circuit that switches current into a high-Q on-chip air-core transformer which provide high efficiency and low radiated emissions. The integrated transformer uses thin film polymer as the insulation barrier. Power transferred to the secondary side is rectified and regulated to a value of 3.3 V or 5 V, depending on the setting of the SEL pin. The secondary (VISO) side control er regulates the output by creating a PWM control signal that is sent to the primary side by a dedicated isolated data channel. The PWM modulates the oscil ator circuit to control the power being sent to the secondary side. Feedback al ows for significantly higher power and efficiency and ensures low overshoots and undershoots during load transients. Undervoltage lockout (UVLO) with hysteresis is integrated on the VCC and VISO supplies which ensures robust system performance under noisy conditions. An integrated soft-start mechanism ensures control ed inrush current and avoids any overshoot on the output during power up. Short-circuit protection: TDA51S-41HC has current-limiting protection to prevent the drive circuit from short-circuiting to positive and negative supply voltages. The power dissipation increases when a short circuit occurs. The short-circuit protection function protects the driver stage from damage. The high-speed isolated data channels use a simple ON-OFF keying (OOK) modulation scheme to transmit signal across the SiO2 isolation capacitors that provide a robust insulation between two different voltage domain and act as a high frequency signal path between the input and the output. The transmitter (TX) modulates the input signal onto the carrier frequency, that is, TX delivers high frequency signal across the isolation barrier in one input state and delivers no signal across the barrier in the other input state. Then the receiver rebuilds the input signal according to the detected in-band energy. The capacitor-based signal path is ful y differential to maximize noise immunity, which is also known as common-mode transient immunity. The capacitively-coupled architecture provides much higher electromagnetic immunity compared to the inductively coupled one. 2023.10.26-A/4
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