Techniques for high impedance current sensing and slope compensation, common challenges for current mode switched mode power supplies (SMPS), are presented. DCR sensing, limited by conventional low impedance sensing techniques, is thus possible, enabling power efficiency gains. Auto-ranging slope compensation based on a multiplication of input voltage VIN and switching frequency fsw allows for truer current mode operation and superior line transient response for a wide range of VIN and fsw. The techniques are demonstrated in an automotive-class 60 V VIN buck controller at 150-600 kHz in a 0.35 mum BiCMOS technology. Offset error <3 mV over 0-10 V and single-cycle stable current loop response are measured.