RICOH R1211x SERIES PWM STEP-UP DC DC CONTROLLER
Summary
The R1211x Series is a high-efficiency, CMOS-based PWM step-up DC/DC controller ideal for creating stable constant voltage power sources in portable electronic equipment. This technical manual provides comprehensive details on the integrated circuit's functionality, including internal soft start and latch-type protection circuits. It covers various operational specifications (input range, oscillator frequency), selection guide nuances, pin configurations, and performance data necessary for engineers designing reliable powered systems like LCD or CCD constant voltage supplies.
Page 1 Text Content
R1211x SERIES
PWM STEP-UP DC/DC CONTROLLER
NO.EA-088-120201
OUTLINE The R1211x Series are CMOS-based PWM step-up DC/DC converter controllers with low supply current. Each of the R1211x Series consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low ripple, high efficiency step-up DC/DC converter can be composed of this IC with some external components, or an inductor, a diode, a power MOSFET, divider resisters, and capacitors. Phase compensation has been made internally in the R1211x002B/D Series, while phase compensation can be made externally as for R1211x002A/C Series. B/D version has stand-by mode. Max duty cycle is internally fixed typically at 90%. Soft start function is built-in, and Soft-starting time is set typically at 9ms(A/B, 700k Hz version) or 10.5ms(C/D, 300k Hz version). As for the protection circuit, after the soft-starting time, if the maximum duty cycle is continued for a certain period, the R1211x Series latch the external driver with its off state, or Latch-type protection circuit works. The delay time for latch the state can be set with an external capacitor. To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector threshold level), or once after making the circuit be stand-by with chip enable pin and enable the circuit again.
FEATURES • Input Voltage Range .........................................2.5V to 6.0V • Oscillator Frequency (PWM control).................300k Hz, 700k Hz • Maximum Duty Cycle ........................................Typ. 90% • Standby Current ................................................Typ. 0μA (for B/D version) • Feedback Voltage .............................................1.0V • Feedback Voltage Accuracy..............................±1.5% • UVLO Threshold level.......................................Typ. 2.2V (Hysteresis Typ. 0.13V) • Feedback Voltage Temperature Coefficient ......±150ppm/°C • Built-in Latch-type Protection Circuit.................Protction Delay Time can be set with an external capacitor • Packages ..........................................................SON-6, SOT-23-6W
APPLICATIONS • Constant Voltage Power Source for portable equipment. • Constant Voltage Power Source for LCD and CCD.
Page Summary Contents For RICOH R1211x SERIES PWM STEP-UP DC DC CONTROLLER
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 36 |
| File Size | 406.15 KB |
| Published | June 05, 2026 |
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Frequently Asked Questions
How can I reset the R1211x protection circuit after a latch event?
Reset by powering on (voltage supplier equal to or less than UVLO detector threshold), or by placing the circuit in stand-by mode using the chip enable pin and re-enabling it.
Which R1211x versions include standby capability and internal phase compensation?
The B/D versions offer Stand-by mode and internal phase compensation.
What is the recommended input voltage range for this DC/DC controller?
The Input Voltage Range is specified as 2.5V to 6.0V.
Does external component usage affect the R1211x's performance?
A low ripple, high efficiency step-up converter can be composed of this IC along with an inductor, diode, power MOSFET, divider resistors, and capacitors.