Micrel, Inc. MIC2179 MIC2179
1.5A Synchronous Buck Regulator General Description Features The Micrel MIC2179 is a 200kHz synchronous buck (stepdown) switching regulator designed for high-efficiency, battery-powered applications.
The MIC2179 operates from a 4.5V to 16.5V input and features
internal power MOSFETs that can supply up to 1.5A output
current. It can operate with a maximum duty cycle of 100%
for use in low-dropout conditions. It also features a shutdown
mode that reduces quiescent current to less than 5ВµA.
The MIC2179 achieves high efficiency over a wide output
current range by operating in either PWM or skip mode. The
operating mode is externally selected, typically by an intelligent system, which chooses the appropriate mode according
to operating conditions, efficiency, and noise requirements.
The switching frequency is preset to 200kHz and can be
synchronized to an external clock signal of up to 300kHz.
The MIC2179 uses current-mode control with internal current
sensing. Current-mode control provides superior line regulation and makes the regulator control loop easy to compensate.
The output is protected with pulse-by-pulse current limiting
and thermal shutdown. Undervoltage lockout turns the output
off when the input voltage is less than 4.5V.
The MIC2179 and is packaged in a 20-lead SSOP package
with an operating temperature range of вЂ“40В°C to +85В°C. 4.5V to 16.5V input voltage range Dual-mode operation for high efficiency (up to 96%) PWM mode for > 150mA load current Skip mode for <150mA load current 150mО© internal power MOSFETs at 12V input 200kHz preset switching frequency Low quiescent current 1.0mA in PWM mode 600ВµA in skip mode < 5ВµA in shutdown mode Current-mode control Simplified loop compensation Superior line regulation 100% duty cycle for low dropout operation Current limit Thermal shutdown Undervoltage lockout Typical Application Applications High-efficiency, battery-powered supplies
Buck (step-down) dc-to-dc converters
Laptop computers …