The **TDA1560** is a high-efficiency integrated Class-H audio power amplifier designed primarily for automotive applications. Its unique feature is its ability to switch between standard operation and a high-power mode using internal lift-up capacitors. --- ## 1. Key Technical Specifications The TDA1560 is known for delivering high output power without requiring a DC-to-DC converter. | Parameter | Specification | |---|---| | **Output Power** | 40W (Class-B) / 30W (High Efficiency) | | **Max Peak Power** | 40W @ 8Ω / 14.4V | | **Supply Voltage** | 8V to 18V (Typical 14.4V) | | **Package** | SIL17P (Single-In-Line 17-pin) | | **Distortion (THD)** | 0.05% @ 20W | --- ## 2. Core Electronic Components & Pins To function correctly, the TDA1560 requires several external components that define its operational modes. ### A. The Lift-up Capacitors This is the most critical part of the TDA1560 circuit. - **Function:** These capacitors store charge and provide a temporary voltage boost (double the supply voltage) during high-signal peaks. - **Typical Value:** Usually two electrolytic capacitors (e.g., 4700µF) connected to pins 12, 14, 15, and 17. ### B. Mode Selection (Pin 16) The chip operates in three modes based on the voltage applied to the Mode pin: 1. **Standby:** Ultra-low current consumption. 2. **Mute:** Input is suppressed to prevent "pops" during startup. 3. **Operating:** Full power mode. ### C. Signal Input - **Coupling Capacitors:** Small film or electrolytic capacitors (e.g., 0.47µF) are used at the input (Pin 1 and 2) to block DC bias from the source. --- ## 3. Class-H Operation Logic The TDA1560 is unique because it transitions between modes based on signal intensity: 1. **Low Power (Class-B):** For signals below a certain threshold, the amplifier works like a standard Class-B amp using the 14.4V rail. 2. **High Power (Class-H):** When the signal peak exceeds the supply rail, the internal switches activate the **lift-up capacitors**. This effectively doubles the voltage available to the power transistors, allowing for 40W output without a dedicated step-up power supply. --- ## 4. Basic Circuit Implementation Below is a simplified representation of how the TDA1560 is wired: ```text [Vcc 14.4V] ----+----[Pin 7, 11] | [Cap 4700uF]----[Pin 14/15] (Lift-up Cap 1) | [Cap 4700uF]----[Pin 12/17] (Lift-up Cap 2) | [Audio In] ----[0.47uF]----[Pin 1] ``` --- ## 5. Thermal and Protection Features The TDA1560 includes integrated protection circuitry to ensure reliability in car environments: * **Thermal Protection:** Reduces output power if the silicon temperature exceeds 150°C. * **Short Circuit Protection:** Protects the output stages against shorts to ground or the supply rail. * **Load Dump:** Can withstand high voltage spikes common in automotive alternators.