An electrostatic discharge (ESD) protection device formed in the semiconductor layer of a semiconductor-on-insulator device, wherein the semiconductor layer has first and second wells. A discharge circuit is formed in the first well, operable to discharge the ESD pulse to ground. A pump circuit is formed in the second well, operable to use a portion of an ESD pulse's voltage to pump current into the first well for allowing the discharge circuit to turn on uniformly. The discharge circuit has a plurality of body nodes to the first well. The pump circuit comprises an input pad for receiving a portion of the ESD pulse's voltage; an MOS transistor having source, gate and drain; a capacitor connected between the input pad and the gate, whereby a rising input voltage pulls the gate transiently high for pumping current into the first well; the source is connected to the body nodes of the discharge circuit, and the drain connected to the input pad.