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 V_(IN) and switching frequency f_(sw) allows for truer current mode operation and superior line transient response for a wide range of V_(IN) and f_(sw). The techniques are demonstrated in an automotive-class 60V V_(IN) buck controller at 150-600kHz in a 0.35μm BiCMOS technology. Offset error <3mV over 0-10V and single-cycle stable current loop response are measured.
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