RICOH Manuals

The R1290 series are optimized DC/DC converter ICs for TFT LCD displays. Each of the R1290 series contains one PWM step-up DC/DC converter controller and two diode charge-pump controllers. The charge-pumps can control a boost output and a negative output and have the output voltage regulation function with external resistors. The power on sequence can be made with setting the delay time with external capacitors for each charge pump channel.

The R1232D series is a CMOS-based PWM step-down DC/DC converter with synchronous rectifier and low supply current. A 10μF or greater ceramic capacitor can be used as the output capacitor with the R1232D. Each of these ICs consists of an oscillator, a PWM control circuit, a voltage reference unit, an error amplifier, a soft-start circuit, protection circuits, a protection against miss operation under low voltage (UVLO), a chip enable circuit, a synchronous rectifier, Nch. driver transistor, and so on. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with only a few kinds of external components, or an inductor and capacitors. (As for R1232D001x type, divider resistors are also necessary.) In terms of the output voltage, it is fixed internally in the R1232Dxx1x types. While in the R1232D001x types, the output voltage is adjustable with external divider resistors. As protection circuits, current limit circuit which limits peak current of LX at each clock cycle, and latch type protection circuit exist. The latch protection works if the term of the over-current condition keeps on a certain time. Latch-type protection circuit works to latch an internal driver with keeping it disable. To release the condition of protection, after disable this IC with a chip enable circuit, enable it again, or restart this IC with power-on or make the supply voltage at U1 less than 3V.

The R1232D Series are low supply current CMOS-based PWM step-down DC/DC converters with synchronous rectifier. R1232D includes a soft start circuit, under-voltage lockout circuit (UVLO) and latch type protection circuit. By simply using an inductor, a capacitor, and (resistors) as external components, a high-efficiency step-down DC/DC converter can be easily configured. R1232D comes in two types: R1232Dxx1A/B with internally fixed output voltage and R1232D001C/D with adjustable output voltage with external resistors.

RP504x series is a low supply current CMOS-based PWM/VFM step-down DC/DC converter with synchronous rectifier. RP504K/L can be switched from two control types by inputting signal to the MODE pin - forced PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. (RP504N Series can be selected from forced PWM control or PWM/VFM auto switching control.) RP504x includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using an inductor and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. The small inductor (2.2μH) and output capacitor (4.7μH) can be used by the switching of 2.25MHz. In addition to SOT-23-5 and DFN1616-6B packages, a 1.2mm × 1.6mm DFN(PLP)1216-6B package is also available.

The RP503x Series are low supply current CMOS-based 600mA∗ step-down DC/DC Converters with synchronous rectifier. Each of these ICs consists of an oscillator, a switching control circuit, a reference voltage unit, an error amplifier, a soft-start circuit, UVLO circuit, a latch protection circuit, switching transistors, and so on. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with only an inductor and capacitors. In terms of the output voltage, since the feedback resistances are built-in, the voltage is fixed internally. 0.1V step output can be set by laser-trim and 1.5% or 18mV tolerance depending on the output voltage is guaranteed. RP503x is PWM/VFM auto switching control in which mode automatically switches from PWM mode to high-efficiency VFM mode in low output current. The efficiency in low output current (VFM mode) improved compared with existing products. As protection circuits, the current limit circuit which limits peak current of Lx at each clock cycle, and the latch type protection circuit which works if the term of the over-current condition keeps on a certain time exist. The latch-type protection circuit works to latch an internal driver with keeping it disable. To release the condition of the protection, after disabling this IC with a chip enable circuit, enable it again, or restart this IC with power-on or make the sup

The RP503x series is a low supply current CMOS-based PWM/VFM step-down DC/DC converters with synchronous rectifier. RP503x is PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. The efficiency in low output current (VFM mode) improved compared with existing products. RP503x includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using an inductor and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured.

The RP502x series of synchronous rectifier step-down DC/DC converters are based on the CMOS process. They contain an oscillator, a reference voltage unit, an error amplifier, a switching control circuit, a soft-start circuit, protection circuits, an UVLO circuit, and switching transistors. Using built-in switch transistors for synchronous rectification, a high-efficiency step-down DC/DC converter is composed of only an inductor and capacitors. As protection circuits, the ICs contain a current limit circuit and a latch protection circuit. The current limit circuit controls the peak current of LX at each clock cycle. If the load current exceeds the limit value for a certain period of time, the latch protection circuit maintains the built-in driver in OFF state. To cancel the latch protection, disable the ICs with a chip enable circuit and then enable it again, or make the power supply voltage lower than UVLO. The setting voltage for the RP502x series is the output voltage fixed type with built-in feedback resistance that is adjustable in 0.1V step with the accuracy of ± 1.5% or ±24mV. The packages for the ICs are WLCSP-6-P2 and DFN1616-6, which enable the high-density mounting. The switching mode for the ICs is selectable from the PWM/VFM auto switching type, which achieves the high efficiency at the light load condition or PWM fixed type, which switches at the fixed frequency.

The RP502x Series are low supply current CMOS-based PWM/VFM step-down DC/DC converters with synchronous rectifier. RP502x can be selected from two control types - fixed PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. RP502x includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using an inductor and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. The small inductor (1.0μH/2.2μH) and small output capacitor (4.7μF) can be used by the switching of 3.3MHz.

RP501K series are CMOS-based step-down DC/DC converters with synchronous rectifier.

The RP501K series are low supply current CMOS-based PWM/VFM step-down DC/DC converters with synchronous rectifier. RP501K can be selected from two control types by input signal to the MODE pin - fixed PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. RP501K includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using an inductor and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. The small inductor (2.2μH) can be used by the switching of 2.25MHz. The frequency accuracy improved to ±10%.

RP500x Series 600mA* Step-down DC/DC Converter with Synchronous Rectifier

The RP500x Series is a low supply current CMOS-based PWM/VFM step-down DC/DC converter with synchronous rectifier. RP500x can be selected from two control types - fixed PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. RP500x includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using an inductor and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured.

The RP506K Series are low supply current CMOS-based PWM/VFM step-down DC/ DC converters with synchronous rectifier featuring 2A*1 output current. Internally, a single IC consists of an oscillator, a reference voltage unit, an error amplifier, a switching control circuit, a mode control circuit, a soft start circuit, a latch protection circuit, an under-voltage lockout (UVLO) circuit, a thermal shutdown circuit, and switching transistors. By simply using an inductor and capacitors as external components, without connecting any diode, a low ripple and high efficiency synchronous rectifier step-down DC/ DC converter can be easily configured. RP506K is available in DFN(PLP)2527-10 package which achieves high-density mounting on boards. RP506K is available in the fixed output voltage type (RP506Kxx1A/ B/ D/ E) which can be set by 0.1 V step and the output voltage accuracy is as high as ±1.5% or ±18mV, or the adjustable output voltage type (RP506K001C/ F) which can be set by using the external resistors. The oscillator frequency can be selected from 2.25MHz (RP506Kxx1A/ B/ C) or 1.2MHz (RP506K001C/ F). By inputting a signal to MODE pin, RP506K can choose PWM/VFM auto switching control or forced PWM control. In low output current, PWM/VFM auto switching control automatically switches from PWM mode to VFM mode in order to achieve high efficiency.

RP506K series 2A PWM/VFM step-down DC/DC converter with synchronous rectifier. RP506K can be selected from two control types by input signal to the MODE pin - forced PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. The xx1A/B/D/E version with an internally fixed output voltage type and the 001C/F version with an externally adjustable output voltage type are available. RP506K includes a soft start circuit, an under-voltage lockout circuit (UVLO), thermal shutdown circuit and a latch protection circuit. By simply using an inductor, (resistors) and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. The oscillator frequency can be selected from 1.2MHz or 2.25MHz.The soft start time is Typ. 0.15ms, and by connecting an external capacitor to TSS pin, soft start time is adjustable. VOUT/VFB pin voltage is monitored, and the output voltage errors can be output from PG pin. The PG pin is N-channel open drain output type. The DFN(PLP)2527-10 package is available.