34V Input Synchronous Step Down DC-DC Controller
Ricoh has launched the high-voltage step down dc-dc converter controller R1272 for general, industrial and automotive applications. The R1272 is especially designed as a power supply for core application processors used in set top boxes, media players, internet gateways and car infotainment/navigation systems. Such systems provide advanced functionalities and require a low operating voltage and high current power supply.
The R1272 has a wide input voltage range up to 34V and an adjustable output voltage from 0.7V to 5.3V. An additional external high side and low side NMOS transistor is required for the R1272 dc-dc converter controller. The total circuit is able to provide an output current up to a maximum of 20A. The oscillator frequency is adjustable in a range from 250kHz to 1MHz through the use of an external resistor and can be synchronized with an external clock when multiple dc-dc converters are used in the power supply.
The phase compensation can also be adapted through an external resistor and capacitor in order to do optimizations for the inductor and output capacitor. To improve efficiency performance under light load conditions, the R1272 is able to switch automatically from pwm into vfm mode, but can be set in a fixed pwm mode as well.
The R1272 features an array of embedded safety circuits and other advanced functions, such as: Current limit function to control the maximum inductor peak current; Hiccup-mode (non-latch type) or latch type over current protection; Thermal shutdown disables the IC at over temperature; UVLO (Under Voltage Lock Out) disables the IC below a minimum input voltage level; Soft-start circuit assures the output voltage to ramp up smoothly; Low-inductor current shutdown; Flag output to provide the output voltage status, a fault signal is provided in case a protection circuit is active or when the IC is not ready for normal operation; Spread Spectrum Clock Generation for EMI reduction; and External start-up tracking voltage function.
Ricoh recently expanded its product portfolio into general, industrial and automotive quality classes, respectively products for common use, products for industrial use with extended high temperature range and products targeted for automotive use compliant to AEC-Q100. The industrial and automotive class products have passed a screening in an extended operating temperature environment and reliability test procedures. Next to the quality class ranking, Ricoh now offers a new Product Longevity Program (PLP) for applications with a lifecycle of 10 years or more. The R1272 will be available for all above quality classes and the PLP program.
