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CIRCUIT NOTEBOOK Interesting circuit ideas which we have checked but not built and tested. Contributions will be paid for at standard rates. All submissions should include full name, address & phone number. Revised “GPS” Analog Clock for NTP module I built the GPS-synchronised Analog Clock Driver (February 2017; siliconchip.com.au/Article/10527), but instead of a GPS module, I used the Clayton’s “GPS” time source (April 2018; siliconchip.com.au/Article/ 11039), which gets its time from the internet using the NTP protocol. The problem I ran into is that the ESP8266 microcontroller with WiFi draws considerably higher peak currents than a GPS module. With spikes above 200mA, the power supply in the Analog Clock Driver was not up to the task. Circuit Ideas Wanted siliconchip.com.au So I modified the Analog Clock Driver circuit as shown here, substituting the MAX756-based boost regulator with a MAX1760-based circuit, shown in the red box. The MAX1760 can supply up to 800mA; more than enough to power the ESP8266 module. Besides changing the chip, the inductor value is significantly lower as the MAX1760 operates at a higher frequency, and it requires a few extra passive components. As the MAX1760 only comes in SMD packages, I chose the 10-pin MSOP version and soldered it to a commonly available MSOP-to-DIL adaptor. I then mounted most of its external components immediately at the adaptor connection points. Five points need to be wired back to the Analog Clock Driver board. I purchased the 3.3µH inductor and the output electrolytic filter capacitor from Mouser. They are both very small, minimising conductor path lengths. This resulted in a unit that synchronises with NTP time reliably. Graeme Dennes, Bunyip, Vic. ($100) Got an interesting original circuit that you have cleverly devised? We will pay good money to feature it in Circuit Notebook. We can pay you by electronic funds transfer, cheque or direct to your PayPal account. Or you can use the funds to purchase anything from the SILICON CHIP Online Store, including PCBs and components, back issues, subscriptions or whatever. Email your circuit and descriptive text to editor<at>siliconchip.com.au Australia’s electronics magazine May 2021  83