4 TPS92201 Design in Video Doorbell, Security Cam

TPS92201 integrate analog dimming function converts digital PWM signal from SOC into FB pin as a voltage level. The TPS92201 is a high-efficiency, Adaptive off-time with peak current control scheme is adapted in the TPS92201. To get the smallest output ripple, the device operates at typically 1.5-MHz pulse width modulation (PWM) mode in full current range, At light load, the device automatically enters pulse frequency modulation (PFM) to maintain high efficiency over the entire load current range.

Figure 4-1 TPS92201 Simplified Schematic

Compare with industry common design.

• Do not need extra resistor and capacitor. Can save the cost.
• Do not need to use resistor as a combination for current adjustment. Just Use the Simple PWM signal.
• Smaller ripple due to Adaptive off-time with peak current control scheme is adapted in the TPS92201
• The feedback reference produces a precise ±5% voltage reference over whole temperature range when the PWM duty cycle is 100%, which is typically 100mV. In analog dimming mode, the feedback voltage is proportional to the duty cycle of PWM input as shown in Figure 4-1.

The following images are bench test results including efficiency and FB linearity and accuracy compared with TPS92201 and current design.

Figure 4-2 Efficiency_1IR_2.7V

Figure 4-4 Efficiency_1IR_5.5V

Figure 4-6 Dimming Accuracy and Linearity

Figure 4-3 Efficiency_1IR_3.6V

Figure 4-5 Efficiency_2IR_5.5V