Step up voltage regulator

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johnny bravo

johnny bravo

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Oct 29, 2009
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I was looking at battery holders for doing my own 5v mod, and came across some that had a built in 5v regulator that steps up the voltage from 1 or 2 batteries and regulates the voltage to 5v, or some that are adjustable from 2.5-5.5v.
Here is an example Pololu - Bodhilabs VPack5.0V 2-AA Battery Holder w/ 5V Regulator

I saw that the amperage was limited on this one (200mah) so i searched for a standalone step up/regulator and found this
MAX1703 Datasheet - 1-Cell to 3-Cell, High Power (1.5A), Low-Noise, Step-Up DC-DC Converter

it is rated at 1.5 amps. What do you think? I thought maybe 1 C battery stepped up to 5v, @ 1.5 v its ~4500-8000mah, so @ 5v would that be 1350-2400mah?

Got my battery info from List of battery sizes - Wikipedia, the free encyclopedia

Any thoughts or criticism?
 
kinabaloo

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johnny bravo said:
I was looking at battery holders for doing my own 5v mod, and came across some that had a built in 5v regulator that steps up the voltage from 1 or 2 batteries and regulates the voltage to 5v, or some that are adjustable from 2.5-5.5v.
Here is an example Pololu - Bodhilabs VPack5.0V 2-AA Battery Holder w/ 5V Regulator

I saw that the amperage was limited on this one (200mah) so i searched for a standalone step up/regulator and found this
MAX1703 Datasheet - 1-Cell to 3-Cell, High Power (1.5A), Low-Noise, Step-Up DC-DC Converter

it is rated at 1.5 amps. What do you think? I thought maybe 1 C battery stepped up to 5v, @ 1.5 v its ~4500-8000mah, so @ 5v would that be 1350-2400mah?

Got my battery info from List of battery sizes - Wikipedia, the free encyclopedia

Any thoughts or criticism?
Click to expand...

Current output would be limited by the internal resistance of the cell. So for high current apps like e-cigs, nothing to be gained with voltage step-ups. It might work, but it won't work much, if at all, better than using the cell directly (if it was 3.7v; 1.5v will not work at all).

In other words, one can't step up the power (no free energy).
 
Last edited:
Scottbee

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Kinabaloo is mistaken on this one. Step-up DC-DC converters (boost) work exceptionally well in this application (the internal resistance of the cell doesn't come into play.. unless you are using watch batteries). The problem is going to be the 1.5A current limit. Running 5V into a 2.3 Ohm (510) atty requires over 2A.

Higher current version of the same concept (high frequency DC-DC boost switchers) are already being used in some custom mods.. and I believe an introduction is imminent on at least one main-stream mod.
 
Scottbee

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Yes.... 2.5A would be good.... 3A would be better (for margin).

As far as the PT is concerned... it really depends on what kind of PT you have. Many (if not most) actually have a 3.7V battery in them... and all the USB power is doing is keeping the 3.7V battery "topped off" in-between vapes.

There are others that don't have the battery. They try to pull the current out of the USB port.. and if the USB port can deliver it... then great. But since USB 2.0 is only rated for .5A.... it's a crap shoot. Some USB ports will literally shut down when you try to exceed their capabilities.... others will give all the current that they can, but the resulting voltage across the atty will be lower (Ohms Law).
 
WillyB

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Scottbee said:
Yes.... 2.5A would be good.... 3A would be better (for margin).

As far as the PT is concerned... it really depends on what kind of PT you have. Many (if not most) actually have a 3.7V battery in them... and all the USB power is doing is keeping the 3.7V battery "topped off" in-between vapes.

There are others that don't have the battery. They try to pull the current out of the USB port.. and if the USB port can deliver it... then great. But since USB 2.0 is only rated for .5A.... it's a crap shoot. Some USB ports will literally shut down when you try to exceed their capabilities.... others will give all the current that they can, but the resulting voltage across the atty will be lower (Ohms Law).
Click to expand...
I don't think that's correct. USB2 specs (Battery Charging Specification) say up to 1.8A can be be provided. The D+ and D- pins come into play, for signaling.
 
caesar

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Maybe for USB 3.0.

USB 2.0 states clearly that no device is allowed to consume more than 100mA at powerup. After proper negotiation and device recognition, the device can signal that it needs more - up to 500mA and can use them only if allowed.

Most motherboards deliver all they can if a pass-through is connected. That's good for vaping but very bad for the motherboard.

A limiting device in the PT is recommended so it won't go over 500mA!
 
WillyB

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caesar said:
Maybe for USB 3.0.

USB 2.0 states clearly that no device is allowed to consume more than 100mA at powerup. After proper negotiation and device recognition, the device can signal that it needs more - up to 500mA and can use them only if allowed.

Most motherboards deliver all they can if a pass-through is connected. That's good for vaping but very bad for the motherboard.

A limiting device in the PT is recommended so it won't go over 500mA!
Click to expand...
You sure? I can't understand then how my 2 PT's ( no batteries) could possibly operate at 500mA. I must be reading the spec wrong.

Can you explain what this means?

In Battery Charging Specification[33], new powering modes are added to the USB specification. A host or hub Charging Downstream Port can supply a maximum of 1.5 A when communicating at low-speed or full-speed, a maximum of 900 mA when communicating at high-speed, and as much current as the connector will safely handle when no communication is taking place; USB 2.0 standard-A connectors are rated at 1500 mA by default. A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured.

 
Scottbee

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WillyB said:
You sure? I can't understand then how my 2 PT's ( no batteries) could possibly operate at 500mA. I must be reading the spec wrong.

Can you explain what this means?

In Battery Charging Specification[33], new powering modes are added to the USB specification. A host or hub Charging Downstream Port can supply a maximum of 1.5 A when communicating at low-speed or full-speed, a maximum of 900 mA when communicating at high-speed, and as much current as the connector will safely handle when no communication is taking place; USB 2.0 standard-A connectors are rated at 1500 mA by default. A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured.
Click to expand...

If you read the Wiki links I believe that you will find that the BCS is a draft.. a proposal (inked in 2009) for a system that can use the USB ports for charging. It is not part of the USB 2.0 specification... and the hardware to support the BCS is not implemented in the vast majority of existing systems. Heck, the BCS calls for charging current that is in excess of what the actual USB connector is even rated for!

Anyway... this is a draft of something that could perhaps be implemented in the future.
 
Ez Duzit

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