Tag Archives: Switching

1A from the sugar cube sized module


With continuous improvement TRACO unveils the SMD version of enormously successful 1A DC/DC converter, the TSR1SM.

The TSR1SM series models of step-down switching regulators (non isolating – POL) have a high efficiency up to 96 % which allows full load operation up to +65°C ambient temperature without the need of any heat transmission layer. Excellent output voltage accuracy (±2%) and low standby current (~1 μA) are features that distinguish these switching regulators from linear regulators.To make a SMD version of such a DC/DC converter is not a simple task, the package should withstand temperatures up to 245°C, used in a lead free soldering ovens. TRACO solved successfully this problem and the TSR1SM is qualified for lead free soldering processes as per J-STD-020D.01 (to find at: www.jedec.org – free registration required) with max. peak body temperature 245°C. Also low MSL level 1 allows PCB washing after soldering with baking at 100°C for 30min.

For applications which require lower supply currents up to 0,5Amps, there is a TSR0,5(SM)series of DC/DC converters with better price level available.

1A from the sugar cube sized module – [Link]

MC34VR500V1ES Multi-Output DC/DC Regulator

The circuit in this reference design features the capability of MC34VR500V1ES to supply multiple DC voltage outputs. This device is designed to support the LS1/T1 family of communication processors, which require efficient and precise level of voltage supplies. With its four switching and five linear regulators, the MC34VR500V1ES can supply power to the whole system, e.g., the processor, memory, system peripherals.

The MC34VR500V1ES device runs with a supply voltage ranging from 2.8V to 4.5V. It can provide nine outputs. Four of these outputs (SW1-4) are buck regulators while the rest (LDO1-5) are general purpose LDOs. Each one of the buck regulator is capable of operating in Pulse Frequency Modulation (PFM), Auto Pulse Skip (APS), and Pulse Width Modulation (PWM) switching modes. These buck regulators also have a current limit feature that generates a fault interrupt whenever there is an overcurrent condition. The SW1 output is capable of providing 0.625-1.875V/4.5A supply while SW2 and SW3 can provide 0.625-1.975V/2A and 0.625-1.975V/2.5A, respectively. The SW1, SW2 and SW3 voltages can be varied with a step size of 25mV. The SW4 output is half of the voltage output of SW3. The general output LDOs can output voltages ranging from 1.8-3.3V with a step size of 100mV except for LDO1 which can only give 0.8-1.55V output with 50mV step size. The LDO1 output can provide current up to 250mA, while LDO2 and LDO4 can output up to 100mA only. The LDO5 output can provide 200mA of current while LDO3 can output up to 350mA. Aside from these nine outputs, the MC34VR500V1ES also have a REFOUT output dedicated for DDR memory reference voltage. The voltage of this REFOUT output is usually half of the SW3 output and can only provide up to 10mA of current. The MC34VR500V1ES outputs can be changed by programming it via the I2C interface.

The operation of the MC34VR500V1ES can be reduced to four states, or modes: ON, OFF, Sleep, and Standby. For the device to turn ON, the input voltage must surpass a voltage threshold of 3.1V, the EN pin must be high, and PORB is de-asserted. The 34VR500 enters the OFF mode when the EN pin is low or there is a thermal shutdown event that forces the device into the OFF mode. Standby mode is usually entered when the STBY pin is asserted for low-power mode of operation. The device only goes into sleep mode if the EN pin is de-asserted. To exit sleep mode, assert the EN pin.

MC34VR500V1ES Multi-Output DC/DC Regulator – [Link]

Bias generators with ultralow noise and ripple for sensitive circuits


The LT®3095 generates two low-noise bias supplies from a common input voltage ranging from 3V to 20V. Each channel includes a fixed frequency, peak current-mode step-up switching regulator and a low-noise, singleresistor- programmable 50mA linear regulator. The linear regulator’s high power supply ripple rejection (PSRR) combined with its low-noise performance results in less than 100μVP-P output ripple and noise.

Bias generators with ultralow noise and ripple for sensitive circuits – [Link]

1A, 2 MHz, 60V boost/SEPIC/inverting DC/DC converter, 6µA Iq


by Graham Prophet:

LT8330 is a current mode, 2 MHz step-up DC/DC converter with an internal 1A, 60V switch. It operates from an input voltage range of 3V to 40V, making it suitable for applications with input sources ranging from a single-cell Li-Ion to automotive inputs.

The device can be configured as either a boost, SEPIC or an inverting converter. It uses a fixed 2 MHz switching frequency, enabling designers to minimise external component sizes and avoid critical frequency bands, such as AM radio. Burst Mode operation reduces quiescent current to 6 µA while keeping output ripple below 15 mVP-P. The combination of a 3 x 2 mm DFN or TSOT-23 package and tiny externals ensures a very compact footprint while minimising overall cost.

1A, 2 MHz, 60V boost/SEPIC/inverting DC/DC converter, 6µA Iq – [Link]

LTC3335 – Nanopower Buck-Boost DC/DC with Integrated Coulomb Counter


The LTC®3335 is a high efficiency, low quiescent current (680nA) buck-boost DC/DC converter with an integrated precision coulomb counter which monitors accumulated battery discharge in long life battery powered applications. The buck-boost can operate down to 1.8V on its input and provides eight pin-selectable output voltages with up to 50mA of output current.

The coulomb counter stores the accumulated battery discharge in an internal register accessible via an I2C interface. The LTC3335 features a programmable discharge alarm threshold. When the threshold is reached, an interrupt is generated at the IRQ pin.

To accommodate a wide range of battery types and sizes, the peak input current can be selected from as low as 5mA to as high as 250mA and the full-scale coulomb counter has a programmable range of 32,768:1.

LTC3335 – Nanopower Buck-Boost DC/DC with Integrated Coulomb Counter – [Link]

Power supply IC generates low-noise bipolar (+/-) power rails


by Graham Prophet @ edn-europe.com:

LTC3265 is a high voltage, highly integrated, low noise dual output power supply IC which takes a single positive input supply (VIN_P) and generates low noise bipolar rails up to ±2•VIN_P without any inductors. High voltage boost and inverting charge pumps deliver low noise dual outputs with post-regulating ±50 mA LDOs

The device includes a boost doubling charge pump, an inverting charge pump and two low dropout (LDO) regulators. The boost charge pump has a 4.5V to 16V input range and powers the positive LDO post regulator from its output, VOUT+. The inverting charge pump has a wider input range (4.5V to 32V) which may be connected to either the boost input or output. The negative LDO post regulator is powered from the output of the inverting charge pump, VOUT-. The LTC3265 is suited for a variety of applications that require low noise bipolar supplies from a high voltage input, such as industrial/instrumentation low noise bias generators, portable medical equipment and automotive infotainment systems.

Power supply IC generates low-noise bipolar (+/-) power rails – [Link]

Automatic Light Switching System with Dimmer

Manual switching of outdoor lights in houses or roadways can be sometimes really inconvenient especially when we are far away or still at work. Sometimes this becomes an opportunity for thieves to infiltrate houses or a possibility of accident in roadways if night comes and our outdoor lights are still OFF. That is why the goal of this circuit is to automatically switch ON outdoor lights when it senses that it is getting dark and switch OFF lights when it’s daytime.

This type of light switching system is what we can usually see installed in streetlights or houses that are implementing automatic switching of outdoor lights. The system is not just limited to switching ON/OFF lights, it can also adjust the brightness of the lights so that it can just supply the right amount of luminance on the area required. This system is composed of a photocell, a receptacle, a ballast (with dimming control), and a lamp powered by the 220VAC mains. The photocell measures the light intensity level in an area and sends this data in a form of voltages (ranging from 0-10VDC) for the dimming control of the ballast. Based on the level of light intensity sensed by the photocell, the ballast will adjust the brightness of the lamp.

The whole system is supported by the TE Connectivity dimming receptacle 2213362-1. The photocell and ballast are connected through this receptacle. This dimming receptacle supports ANSI standard dimmable photocells with 5 positions (3 power contacts and 2 dimming signal contacts). Its power contacts can handle voltages up to 480V AC/DC provided that the maximum current passing through it will not exceed 15A. The dimming contacts of this receptacle supports 0-10VDC dimming method with a maximum current of 0.10A

Automatic Light Switching System with Dimmer – [Link]

How to control LM2596 buck-converter with microcontroller

by hugatry @ hackvlog.com:

Every now and then someone asks on different forums if there is an way to control cheap LM2596 modules with an Arduino or another microcontroller. I decided to demonstrate one solution that might be basic electronics for some, but still many don’t know about.

Those buck converters will change the output voltage to make the feedback pin, connected to the output via a voltage divider, become 1.25V or so. If feedback is higher, output gets lower and vice versa. If one changes the ratio of resistors in voltage divider, output voltage will change. This is usually done by turning a trimmer resistor with a screwdriver. That is good enough for many applications where voltage will be set only once, but sometimes there is a need to adjust the output voltage more frequently.

How to control LM2596 buck-converter with microcontroller – [Link]

Buck-boost regulator achieves high efficiency


by Susan Nordyk @ edn.com:

Using adaptive current-limit PFM (pulse frequency modulation) control, the ISL9120 switching regulator from Intersil realizes efficiencies of up to 98%, while automatically transitioning between buck and boost modes without significant output disturbance. The part accommodates a wide input voltage range of 1.8 V to 5.5 V and has an adjustable output voltage range of 1 V to 5.2 V for use with multiple power rails. It is capable of delivering up to 800 mA of output current (VIN = 2.5 V, VOUT = 3.3 V).

Buck-boost regulator achieves high efficiency – [Link]

LM2596 DC-DC Converter Module Testing


by Kerry D. Wong:

LM2596 based step-down DC-DC converter modules can be bought on eBay quite cheaply for around a dollar each. But how do they perform? Is it safe to use it to power your design? Let’s find out.

According to TI’s website, these LM2596 step-down (buck) regulators are sold for $1.8 each for a quantity of a thousand. So how a finished converter could be sold for just above a dollar each is quite a mystery to me. Anyway, the picture below is the board I received. It appears that there are a few variations to this design (slightly different inductor size or capacitor size/voltage rating, etc.) but they all are largely based on the reference design.

LM2596 DC-DC Converter Module Testing – [Link]