SLASEC8B February 2017 – January 2019 PGA460-Q1
The direct-driven method substitutes the traditional center-tap transformer with a bridge driver, and is suitable for plastic-shelled open-top transducers. Any open or closed top transducer can be driven directly, but the maximum amount of SPL may not be generated during transmission. The direct-driven configuration uses either a half-bridge or full-bridge gate driver to generate an alternating square wave to drive the transducer. By default, the half-bridge driver configuration is enabled to allow the use of a single transducer to transmit and receive. The PGA460-Q1 device cannot drive a single transducer in the full-bridge configuration without the addition of external components (beyond the scope of this document).. Because the low-side drivers are integrated into the PGA460-Q1 device, only one external high-side p-channel MOSFET is required. In the half-bridge configuration, one OUTx channel is used to drive the p-channel MOSFET, while the other is used to directly excite the transducer.. Figure 141 shows the direct-driven method schematic for a single transducer.