3.2.2 Transformer less Solution

The design implements a transformer less power management solution to meet component height requirement of less than 5mm.Dual Rail HV (±80 V at 25 mA) generation from 5-V USB with single stage implementation and Point of Load (also supports 3.6-V battery input). Below are the key constraints in the design for power supply in smart probe ultrasound scanners:

• Efficiency > 80%
• Thermal performance (temperature rise <15 °C above ambient)
• SNR > 55dB (Noise floor below -90dB)
• HV Rail accuracy (between +ve and –ve HV lines) 1%
• Load regulation accuracy within 2%

Figure 7 shows the board image of the portion of high voltage circuit implemented in the design. The corresponding section is highlighted in red.

Figure 7. High-voltage Section Implemented in 45mm x 15mm x 4.3mm (complete circuit routed and placed on top layer)