We propose a scalable architecture for a differential single-photon avalanche diode (D-SPAD) array which generates differential timing measurements in lieu of absolute measurements. This design not only reduces the required off-chip data transfer, but also mitigates saturation at the device and at the counter, making it an ideal candidate for high dynamic range (HDR) imaging. The differential nature of the data also obviates the requirement for time to digital converters (TDCs) or TCSPCs. A prototype test structure of 16 pixels was fabricated in 180 nm CMOS, and we show images reconstructed from this chip that illustrate its capabilities.